Bitcoin Wiki - User contributions [en]

User talk:Ibsdirewolf

2026-03-22T12:07:27Z

NotATether: /* Physical bitcoins */ new section

Hello. I'd like to add a new page for Satori Coin physical bitcoins. I will be working on this content if allowed.

== Physical bitcoins ==

Hi, you can just create the page and then after you publish it I will manually approve the edit.

--[[User:NotATether|NotATether]] ([[User talk:NotATether|talk]]) 12:07, 22 March 2026 (UTC)

Zerolink

2026-02-22T12:41:17Z

NotATether: Create page

ZeroLink is a 2017 fungibility framework from Adam Ficsor (nopara73) that turned a loose set of privacy ideas into a concrete wallet architecture. Instead of treating CoinJoin as a single transaction trick, ZeroLink defines coordinator interaction, credential handling, fee logic, output registration, and post-mix wallet behavior. Its Github repository was archived in 2020, but is still accessible.<ref>https://github.com/nopara73/ZeroLink/blob/master/ZeroLink.md</ref>

At a high level, ZeroLink is built on three practical principles that work together. If one part is missing, the privacy benefit drops quickly in real-world usage.

# CoinJoin coordination
# Wallet hygine
# Toxic change policy

Zerolink's coinjoin involves users registering inputs with a coordinator, obtaining blind-signed credentials, and redeeming them for anonymized outputs. It enforces mandatory fresh addresses, randomized fees, and separate change outputs. Wallets automatically quarantine change and avoid merging it back into mixed UTXOs.

== References ==

TumbleBit

2026-02-22T12:35:16Z

NotATether: Explain TumbleBit

TumbleBit is a anonymous payments protocol from 2016 that is fully compatible with today’s Bitcoin protocol. TumbleBit allows parties to make payments through an untrusted Tumbler. No-one, not even the Tumbler, can tell which payer paid which payee during a TumbleBit epoch. TumbleBit consists of two interleaved fair-exchange protocols that prevent theft of bitcoins by cheating users or a malicious Tumbler. TumbleBit combines fast cryptographic computations (performed off the blockchain) with standard bitcoin scripting functionalities (on the blockchain) that realize smart contracts.

TumbleBit was proposed by Ethan Heilman and colleagues as an “untrusted Bitcoin-compatible anonymous payment hub.” It has three different parts. First, users and the tumbler lock coins in a 2-of-2 multisig contract so funds cannot be stolen. Following that, users solve RSA puzzles issued by the tumbler; revealing the solution proves the tumbler must pay them later, but the tumbler does not learn which customer solved which puzzle. The specific type of puzzle being solved is described in detail in the whitepaper. Finally, users redeem their puzzles for fresh outputs, and the tumbler can take its fee.

TumbleBit inspired related implementations such as [https://github.com/NTumbleBit/NTumbleBit NTumbleBit] and Breeze Wallet.

Note that '''A2L''' is faster and uses less bandwidth than TumbleBit.[https://eprint.iacr.org/2019/589.pdf]

==External links==
* https://eprint.iacr.org/2016/575 - The paper
* https://github.com/BUSEC/TumbleBit - Implementation
* https://joinmarket.me/blog/blog/tumblebit-for-the-tumble-curious/
* https://medium.com/@nopara73/tumblebit-vs-coinjoin-15e5a7d58e3
* https://www.youtube.com/watch?v=8BLWUUPfh2Q&t=3787 - Talk at ScalingBitcoin 2016
* https://diyhpl.us/wiki/transcripts/scalingbitcoin/milan/tumblebit/ - Transcript of talk

==References==
<references />

[[Category:Privacy]]

Bitcoin

2026-02-03T06:41:32Z

NotATether: grammar

'''Bitcoin''' is a decentralized [[digital currency]] created by an unknown person or group of people under the name [[Satoshi Nakamoto]] and released as open-source software in 2009. It does not rely on a central server to process transactions or store funds. There are a maximum of 2,099,999,997,690,000 bitcoin elements (called satoshis, the unit has been named in collective homage to the original creator), which are currently most commonly measured in units of 100,000,000 known as BTC. There will only ever be 21 million bitcoin (BTC) to ever be created.

{{As of|January 2018}}, it is the most widely used alternative currency,<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph">{{cite web|title=Quantitative Analysis of the Full Bitcoin Transaction Graph|url=https://eprint.iacr.org/2012/584.pdf|publisher=Cryptology ePrint Archive|accessdate=18 October 2012|author=Ron Dorit|coauthors=Adi Shamir|page=17|quote=The Bitcoin system is the best known and most widely used alternative payment scheme,...}}</ref><ref name="Cryptocurrency Market Capitalization">{{Cite web|title=Coinmarketcap.com|url=https://coinmarketcap.com/}}</ref> now with the total market cap around 250 billion US dollars.<ref>{{cite web|title=Market Capitalization|url=https://coinmarketcap.com/currencies/bitcoin/|publisher=Coinmarketcap.com|accessdate=10 January 2018}}</ref>

Bitcoin has no central issuer; instead, the peer-to-peer network regulates bitcoins, transactions and issuance according to consensus in network software. These transactions are verified by network nodes through the use of cryptography and recorded in a public distributed ledger called a blockchain.

Bitcoins are issued to various nodes that verify transactions through computing power;
it is established that there will be a limited and scheduled release of no more than BTC 21 million worth of coins, which will be fully issued by the year 2140.

Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoins as payment. Research produced by the University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using Bitcoin.

Internationally, bitcoins can be exchanged and managed through various websites and [[software]] along with physical banknotes and coins.<ref>{{Cite web|title=Physical Bitcoins by Casascius|url=https://www.casascius.com/|publisher=Casascius Coins|accessdate=29 September 2012}}</ref><ref>{{Cite web|title=Bitbills|url=http://www.bitbills.com/|publisher=Bitbills|accessdate=29 September 2012}}</ref>

==History==
{{main|History}}

A cryptographic system for untraceable payments was first described by David Chaum in 1982.<ref>[http://blog.koehntopp.de/uploads/Chaum.BlindSigForPayment.1982.PDF David Chaum, Blind signatures for untraceable payments], Advances in Cryptology - Crypto '82, Springer-Verlag (1983), 199–203.</ref> In 1990 Chaum extended this system to create the first cryptographic anonymous electronic cash system.,<ref>{{cite journal|journal=Lecture Notes in Computer Science|last1=Chaum|first1=David|last2=Fiat|first2=Amos|last3=Naor|first3=Moni|title=Untraceable Electronic Cash|url=http://blog.koehntopp.de/uploads/chaum_fiat_naor_ecash.pdf}}</ref> which became known as ecash.
<ref>{{cite web|url=https://www.wired.com/wired/archive/2.12/emoney.html|publisher=Wired|title=E-Money (That's What I Want)|date=1994–2012|author=Steven Levy}}</ref> In 1998 [[Wei Dai]] published a description of an anonymous, distributed electronic cash system which he called "b-money".<ref>{{cite web|title=B-Money|url=http://www.weidai.com/bmoney.txt|author=Wei Dai|year=1998}}</ref> Around the same time, Nick Szabo created ''bit gold''.<ref>{{cite web|url=https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0|title=Bitcoin: The Cryptoanarchists’ Answer to Cash|publisher=IEEE Spectrum|quote=Around the same time, Nick Szabo, a computer scientist who now blogs about law and the history of money, was one of the first to imagine a new digital currency from the ground up. Although many consider his scheme, which he calls “bit gold,” to be a precursor to Bitcoin}}</ref><ref name="bitgold">{{cite web|title=Bit gold|url=https://unenumerated.blogspot.co.uk/2005/12/bit-gold.html|author=Nick Szabo|quote=My proposal for bit gold is based on computing a string of bits from a string of challenge bits, using functions called variously "client puzzle function," "proof of work function," or "secure benchmark function.". The resulting string of bits is the proof of work.... The last-created string of bit gold provides the challenge bits for the next-created string.}}</ref> Like Bitcoin, ''Bit gold'' was a currency system where users would compete to solve a [[proof of work]] function, with solutions being cryptographically chained together and published via a distributed property title registry. A variant of ''Bit gold'', called ''Reusable Proofs of Work'', was implemented by Hal Finney.<ref name="bitgold"/>

In 2008, Satoshi Nakamoto published a [[Bitcoin_white_paper|paper]]<ref name="whitepaper">{{cite web
|last= Nakamoto
|first= Satoshi
|title= Bitcoin: A Peer-to-Peer Electronic Cash System
|url= http://www.cs.kent.edu/~JAVED/class-P2P12F/papers-2012/PAPER2012-p2p-bitcoin-satoshinakamoto.pdf
|accessdate = 14 December 2010
|date= 24 May 2009
|postscript=
}}</ref><ref>{{cite web
|url= https://article.gmane.org/gmane.comp.encryption.general/12588/
|title= Bitcoin P2P e-cash paper
}}</ref> on The Cryptography Mailing list at metzdowd.com<ref>[https://www.mail-archive.com/search?l=cryptography@metzdowd.com&q=from:%22Satoshi+Nakamoto%22 Satoshi's posts to Cryptography mailing list]</ref> describing the Bitcoin protocol.

The Bitcoin network came into existence on 3 January 2009 with the release of the first Bitcoin client, [[wxBitcoin]], and the issuance of the first bitcoins.<ref>{{cite web |title=Block 0 – Bitcoin Block Explorer |url=https://blockexplorer.com/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f }}</ref><ref>{{cite web |url=https://www.mail-archive.com/cryptography@metzdowd.com/msg10142.html |title=Bitcoin v0.1 released}}</ref><ref>{{cite web |url=https://sourceforge.net/news/?group_id=244765 |title=SourceForge.net: Bitcoin}}</ref>
A year after, the initial exchange rates for Bitcoin were set by individuals on the bitcointalk forums.{{Citation needed|date=October 2012}} The most significant transaction involved a BTC 10,000 pizza.<ref>{{cite web|title=The Rise and Fall of Bitcoin|url=https://www.wired.com/magazine/2011/11/mf_bitcoin/|publisher=Wired|accessdate=13 October 2012}}</ref>
Today, the majority of bitcoin exchanges occur on the [[Bitstamp]] bitcoin exchange.<ref>{{cite web | title = Exchange volume distribution | work = by market | publisher = [[Bitcoin Charts]] | date = 15 April 2014 | url = https://bitcoincharts.com/charts/volumepie/ | accessdate = 15 April 2014 }}</ref>

In 2011, Wikileaks,<ref>{{cite news
|last= Greenberg
|first= Andy
|url= http://blogs.forbes.com/andygreenberg/2011/06/14/wikileaks-asks-for-anonymous-bitcoin-donations/
|title= WikiLeaks Asks For Anonymous Bitcoin Donations – Andy Greenberg – The Firewall – Forbes
|publisher= Blogs.forbes.com
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> [[Freenet]],<ref>{{cite web
|url= https://freenetproject.org/donate.html
|title= /donate
|publisher= The Freenet Project
|date=
|accessdate = 22 June 2011
}}</ref> Singularity Institute,<ref>[http://singinst.org/donate/ SIAI donation page]</ref> Internet Archive,<ref>[https://www.archive.org/donate/index.php Internet Archive donation page]</ref> Free Software Foundation<ref>[https://my.fsf.org/donate/other/ Other ways to donate]</ref> and others, began [[Receiving_donations_with_bitcoin|to accept donations in bitcoins]]. The Electronic Frontier Foundation did so for a while but has since stopped, citing concerns about a lack of legal precedent about new currency systems, and because they "generally don't endorse any type of product or service".<ref>{{cite web
|url= https://www.eff.org/deeplinks/2011/06/eff-and-bitcoin
|title= EFF and Bitcoin | Electronic Frontier Foundation
|publisher= Eff.org
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> Some small businesses had started to adopt Bitcoin. LaCie, a public company, accepts bitcoins for its Wuala service.<ref>{{Cite web|url=http://www.wuala.com/en/bitcoin |title=Secure Online Storage – Backup. Sync. Share. Access Everywhere |publisher=Wuala |date= |accessdate = 24 January 2012}}</ref>

In 2012, BitPay reports of having over 1000 merchants accepting bitcoins under its payment processing service.<ref>{{cite web|title=BitPay Signs 1,000 Merchants to Accept Bitcoin Payments|url=http://www.americanbanker.com/issues/177_176/bitpay-signs-1000-merchants-to-accept-bitcoin-payments-1052538-1.html|publisher=American Banker|accessdate=12 October 2012}}</ref>

==Administration==
Bitcoin is administered through a decentralized peer-to-peer network.<ref name="whitepaper"/> Cryptographic technologies and the peer-to-peer network of computing power enables users to make and verify irreversible, instant online bitcoin payments, without an obligation to trust and use centralized banking institutions and authorities. Dispute resolution services are not made directly available. Instead it is left to the users to verify and trust the parties they are sending money to through their choice of methods.

Bitcoins are issued according to rules agreed to by the majority of the computing power within the Bitcoin network. The core rules describing the predictable issuance of bitcoins to its verifying servers, a voluntary and competitive transaction fee system and the hard limit of no more than BTC 21 million issued in total.<ref name="whitepaper"/>

Bitcoin does not require a central bank, State,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/3
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> or incorporated backers.

==Services==
{{main|Wallet}}

Bitcoins are sent and received through software and websites called wallets. They send and confirm transactions to the network through Bitcoin addresses, the identifiers for users' Bitcoin wallets within the network.<ref name="whitepaper"/>

===Bitcoin addresses===
{{main|Address}}

Payments are made to Bitcoin "addresses": human-readable strings of numbers and letters around 33 characters in length, always beginning with the digit 1 or 3. However, newer "[[Segregated Witness|Segwit]]" addresses begin with bc1 and contain entirely numbers and lowercase letters.

Users obtain new Bitcoin addresses from their Bitcoin software. Creating a new address can be a completely offline process and require no communication with the Bitcoin network. Web services usually generate a new Bitcoin address for every user, allowing them to have their own custom deposit address, but sometimes this is not the case.

===Transaction fees===
{{main|Transaction fees}}
Transaction fees may be included with any transfer of bitcoins. While it's technically possible to send a transaction with zero fee, {{as of|2017|lc=on}} it's highly unlikely that one of these transactions confirms in a realistic amount of time, causing most nodes on the network to drop it. For transactions which consume or produce many outputs (and therefore have a large data size), higher transaction fees are usually expected.

===Confirmations===
{{main|Confirmation}}

The network's software confirms a transaction when it records it in a block. Further blocks of transactions confirm it even further. After six confirmations/blocks, a transaction is confirmed beyond reasonable doubt.

The network must store the whole transaction history inside the blockchain, which grows constantly as new records are added and never removed. Nakamoto conceived that as the database became larger, users would desire applications for Bitcoin that didn't store the entire database on their computer. To enable this, the blockchain uses a [[merkle tree]] to organize the transaction records in such a way that client software can locally delete portions of its own database it knows it will never need, such as earlier transaction records of bitcoins that have changed ownership multiple times.

==Economics==

===Initial distribution===

Bitcoin has no centralized issuing authority.<ref name="ars-06-08-11">
{{Cite news
|first= Thomas
|last= Lowenthal
|title= Bitcoin: inside the encrypted, peer-to-peer digital currency
|newspaper= Ars Technica
|date= 8 June 2011
|url= https://arstechnica.com/tech-policy/news/2011/06/bitcoin-inside-the-encrypted-peer-to-peer-currency.ars
}}</ref><ref>{{cite news
|author= Sponsored by
|url= http://www.economist.com/blogs/babbage/2011/06/virtual-currency
|title= Virtual currency: Bits and bob
|publisher= The Economist
|date=
|accessdate = 22 June 2011
}}</ref><ref>{{cite web
|last= Geere
|first= Duncan
|url= https://www.wired.co.uk/news/archive/2011-05/16/bitcoin-p2p-currency
|title= Peer-to-peer currency Bitcoin sidesteps financial institutions (Wired UK)
|publisher= Wired.co.uk
|date=
|accessdate = 22 June 2011
}}</ref> The network is programmed to increase the money supply as a geometric series until the total number of bitcoins reaches 21 million.<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph"/> {{As of|2012|10}} slightly over 10 million of the total BTC 21 million had been created; the current total number created is available online.<ref>{{cite web
|title= Total Number of Bitcoins in Existence
|url= https://blockexplorer.com/q/totalbc
|work= Bitcoin Block Explorer
|accessdate = 3 October 2012
}}</ref> By 2013 half of the total supply will have been generated, and by 2017, three-quarters will have been generated. To ensure sufficient granularity of the [[money supply]], clients can divide each BTC unit down to eight decimal places (a total of 2.1 × 1015 or 2.1 quadrillion units).<ref name="lwn">{{Cite news
|author= Nathan Willis
|date= 10 November 2010
|title= Bitcoin: Virtual money created by CPU cycles
|publisher= LWN.net
|url= https://lwn.net/Articles/414452/
}}</ref>

The network {{As of|2012|lc=on}} required over one million times more work for confirming a block and receiving an award (BTC 25 {{As of|2012|2|lc=on}}) than when the first blocks were confirmed.
The difficulty is automatically adjusted every 2016 blocks based on the time taken to find the previous 2016 blocks such that one block is created roughly every 10 minutes.

Those who chose to put computational and electrical resources toward mining early on had a greater chance at receiving awards for block generations. This served to make available enough processing power to process blocks. Indeed, without miners there are no transactions and the bitcoin economy comes to a halt.

===Exchange rate===
Prices fluctuate relative to goods and services more than more widely accepted currencies;
the price of a bitcoin is not static.

In August 2012, 1 bitcoin traded at around US$10.00. Taking into account the total number of bitcoins mined, the monetary base of the Bitcoin network stands at over USD 110 million.<ref>[http://www.bitcoinwatch.com/ http://www.bitcoinwatch.com/] Bitcoin statistics</ref>

== Anonymity ==
{{main|Anonymity & Security}}

=== Transactions ===

While using bitcoins is an excellent way to make your purchases, donations, and p2p payments without losing money through inflated transaction fees, transactions are never truly anonymous. Buying bitcoin you pass identification, Bitcoin transactions are stored publicly and permanently on the network, which means anyone can see the balance and transactions of any Bitcoin address. Bitcoin activities are recorded and available publicly via the [[blockchain]], a comprehensive database which keeps a record of Bitcoin transactions.

=== Buying/selling bitcoins ===

All exchange companies require the user to scan ID documents, and large transactions must be reported to the proper governmental authority.

This means that a third party with an interest in tracking your activities can use your visible balance and ID information as a basis from which to track your future transactions or to study previous activity. In short, you have compromised your [[security]] and [[privacy]].

In addition to conventional exchanges there are also peer-to-peer exchanges. Peer to peer exchanges will often not collect KYC and identity information directly from users, instead they let the users handle KYC amongst themselves. These can often be a better alternative for those looking to purchase bitcoins quickly and without KYC delay.

=== Mixing services ===

[http://anonymity.co.in/mixing_services.html Mixing services] are used to avoid compromising of privacy and security. Mixing services provide to periodically exchange your bitcoins for different ones which cannot be associated with the original owner.

== Security ==
{{seealso|Weaknesses}}

In the history of Bitcoin, there have been a few [[incidents]], caused by problematic as well as malicious transactions. In the worst such incident, and the only one of its type, a person was able to pretend that he had a practically infinite supply of bitcoins, for almost 9 hours.

Bitcoin relies, among other things, on [https://en.wikipedia.org/wiki/Public-key_cryptography public key cryptography] and thus may be vulnerable to [https://en.wikipedia.org/wiki/Elliptic_curve_cryptography#Quantum_computing_attacks quantum computing attacks] if and when practical quantum computers can be constructed.

If multiple different software packages, whose usage becomes widespread on the Bitcoin network, disagree on the protocol and the rules for transactions, this could potentially cause a fork in the block chain with each faction of users being able to accept only their own version of the history of transactions. This could influence the price of bitcoins.

A global, organized campaign against the currency or the software could also influence the demand for bitcoins, and thus the exchange price.

==Bitcoin mining==
{{main|Mining}}

Bitcoin mining nodes are responsible for managing the Bitcoin network.

Bitcoins are awarded to Bitcoin nodes known as "miners" for the solution to a difficult [[proof-of-work]] problem which confirms transactions and prevents double-spending. This incentive, as the Nakamoto white paper describes it, encourages "nodes to support the network, and provides a way to initially distribute coins into circulation, since no central authority issues them."<ref name="whitepaper" />

Nakamoto compared the generation of new coins by expending CPU time and electricity to gold miners expending resources to add gold to circulation.<ref name="whitepaper"/>

[[File:Cryptocurrency Mining Farm.jpg|right|350px|thumb|Iceland is a good location for [[mining]] bitcoins because of the natural cold temperature.]]

===Node operation===

The node software for the Bitcoin network is based on peer-to-peer networking, digital signatures and cryptographic proof to make and verify transactions. Nodes broadcast transactions to the network, which records them in a public record of all transactions called the ''blockchain'' after validating them with a [[proof-of-work|proof-of-work system]].

Satoshi Nakamoto designed the first Bitcoin node and mining software<ref name="processors">{{Cite news
|last= Davis
|first= Joshua
|title= The Crypto-Currency
|url= https://www.wired.com/magazine/2011/11/mf_bitcoin/all
|accessdate = 11 November 2011
|newspaper= Wired Magazine
|date= 10 November 2011
}}</ref> and developed the majority of the first implementation, Bitcoind, from 2007 to mid-2010.<ref name="code_start">{{cite web
|url= https://bitcointalk.org/index.php?topic=13.msg46#msg46
|title= Questions about Bitcoin
|publisher= Bitcoin forum
|date= 10 December 2009
}}</ref>

Node implementations include core software such as Bitcoind/Bitcoin-Qt, [[libbitcoin]], [[cbitcoin]]<ref>{{Cite web|title=cbitcoin|url=https://github.com/MatthewLM/cbitcoin|accessdate=3 October 2012}}</ref> and [[BitCoinJ|bitcoinj]].<ref>{{cite web
|url= https://news.slashdot.org/story/11/03/23/0210207/Google-Engineer-Releases-Open-Source-Bitcoin-Client
|title= Google Engineer Releases Open Source Bitcoin Client
|author= angry tapir, timothy
|date= 23 March 2011
|publisher= Slashdot
|accessdate = 18 May 2011
}}</ref><ref>{{cite web
|url= http://www.javaworld.com/javaworld/jw-01-2012/120110-bitcoin-for-beginners-3.html?page=1
|title= Bitcoin for beginners: The BitcoinJ API
|author= Dirk Merkel
|date= 10 January 2012
|publisher= JavaWorld
|accessdate = 3 August 2012
}}</ref>

Every node in the Bitcoin network collects all the unacknowledged transactions it knows of in a file called a ''block'', which also contains a reference to the previous valid block known to that node. It then appends a [[nonce]] value to this previous block and computes the SHA-256 cryptographic hash of the block and the appended nonce value. The node repeats this process until it adds a nonce that allows for the generation of a hash with a value lower than a specified ''target''. Because computers cannot practically reverse the hash function, finding such a nonce is hard and requires on average a predictable amount of repetitious trial and error. This is where the ''[[proof-of-work]]'' concept comes in to play. When a node finds such a solution, it announces it to the rest of the network. Peers receiving the new solved block validate it by computing the hash and checking that it really starts with the given number of zero bits (i.e., that the hash is within the target). Then they accept it and add it to the chain.

===Mining rewards===
In addition to receiving the pending transactions confirmed in the block, a generating node adds a ''generate'' transaction, which awards new bitcoins to the operator of the node that generated the block. The system sets the payout of this generated transaction according to its defined inflation schedule. The miner that generates a block also receives the fees that users have paid as an incentive to give particular transactions priority for faster confirmation.<ref>[https://www.bitcoinmining.com Bitcoin Mining]</ref>

The network never creates more than a BTC 50 reward per block and this amount will decrease over time towards zero, such that no more than BTC 21 million will ever exist.<ref name="lwn" /> As this payout decreases, the incentive for users to run block-generating nodes is intended to change to earning [[#Transaction fees|transaction fees]].

===Mining pools===
{{main|Pooled mining}}

Bitcoin users often pool computational effort to increase the stability of the collected fees and subsidy they receive.<ref name="We Use Coins Mining">{{cite web|title=About Bitcoin Mining|url=https://www.weusecoins.com/en/mining-guide/|publisher=We Use Coins|accessdate=27 May 2015}}</ref>

===Mining difficulty===
{{main|Difficulty}}

In order to throttle the creation of blocks, the difficulty of generating new blocks is adjusted over time. If mining output increases or decreases, the difficulty increases or decreases accordingly.

The adjustment is done by changing the threshold that a hash is required to be less than. A lower threshold means fewer possible hashes can be accepted, and thus a higher degree of difficulty. The target rate of block generation is one block every 10 minutes, or 2016 blocks every two weeks. Bitcoin changes the difficulty of finding a valid block every 2016 blocks, using the difficulty that would have been most likely to cause the prior 2016 blocks to have taken two weeks to generate, according to the timestamps on the blocks. Technically, this is done by modelling the generation of bitcoins as Poisson process. All nodes perform and enforce the same difficulty calculation.

Difficulty is intended as an automatic stabilizer allowing mining for bitcoins to remain profitable in the long run for the most efficient miners, independently of the fluctuations in demand of the bitcoin in relation to other currencies.

===Mining hardware===
{{main|Mining Hardware Comparison}}

Bitcoins used to be mined through Intel/AMD CPUs. {{As of | 2012}}, mining has gradually moved to [[GPU]] and [[FPGA]] hardware.<ref name="bitcoinmag-butterfly" /> [[Application-specific integrated circuit|ASIC]]-based hardware for bitcoin mining has been announced by several manufacturers who intend to ship products from late 2012 to early 2013.<ref name="bitcoinmag-butterfly">{{Cite web|title=Bitpay Breaks Daily Volume Record with Butterfly ASIC mining release|url=http://bitcoinmagazine.net/bitpay-breaks-daily-volume-record-with-butterfly-asic-mining-release/|publisher=Bitcoin Magazine}}</ref>

==Concerns==

===As an investment===
{{main|Bitcoin as an investment}}

Bitcoin describes itself as an experimental digital currency. Reuben Grinberg has noted that Bitcoin's supporters have argued that bitcoins are neither securities nor investments because they fail to meet the criteria for either category.<ref name="grinberg">{{cite web | url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1817857 | title=Bitcoin: An Innovative Alternative Digital Currency | publisher=SSRN | date=9 December 2011 | accessdate=4 December 2012 | author=Grinberg, Reuben}}</ref> Although it is a virtual currency, some people see it as an investment<ref name="cnbc">{{cite web | url=http://www.cnbc.com/id/45030812/The_Pros_And_Cons_Of_Biting_on_Bitcoins | title=The Pros And Cons Of Biting on Bitcoins | publisher=CNBC | date=23 November 2011 | accessdate=4 December 2012 | author=Gustke, Constance}}</ref> or accuse it of being a form of investment fraud known as a Ponzi scheme.<ref>{{cite web |url=https://www.theregister.co.uk/2011/06/08/bitcoin_under_attack/ |title=US senators draw a bead on Bitcoin |last1=Chirgwin |first1=Richard |date=8 June 2011 |publisher=The Register |accessdate=14 November 2012}}</ref><ref>{{cite web |url=http://uk.reuters.com/article/2012/04/01/uk-traders-bitcoin-idUKBRE8300JL20120401 |title=Bitcoin, the City traders' anarchic new toy |last1=O'Leary |first1=Naomi |date=2 April 2012 |publisher=Reuters |accessdate=14 November 2012}}</ref> A report by the European Central Bank, using the U.S. Securities and Exchange Commission's definition of a Ponzi scheme, found that the use of bitcoins shares some characteristics with Ponzi schemes, but also has characteristics of its own which contradict several common aspects of Ponzi schemes.<ref name="ecbreport">{{cite web | url=http://www.ecb.europa.eu/pub/pdf/other/virtualcurrencyschemes201210en.pdf | title=Virtual Currency Schemes | publisher=European Central Bank | date=October 2012 | accessdate=4 December 2012}}</ref>

===Privacy===
Because transactions are broadcast to the entire network, they are inherently public. Unlike regular banking,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> which preserves customer privacy by keeping transaction records private, loose transactional privacy is accomplished in Bitcoin by using many unique addresses for every wallet while at the same time publishing all transactions. As an example, if Alice sends BTC 123.45 to Bob, the network creates a public record that allows anyone to see that 123.45 has been sent from one address to another. However, unless Alice or Bob make their ownership of these addresses known, it is difficult for anyone else to connect the transaction with them. However, if someone connects an address to a user at any point they could follow back a series of transactions as each participant likely knows who paid them and may disclose that information on request or under duress.

It can be difficult to associate Bitcoin identities with real-life identities.<ref name="An Analysis of Anonymity in the Bitcoin System">Fergal Reid and Martin Harrigan (24 July 2011). [https://anonymity-in-bitcoin.blogspot.com/2011/07/bitcoin-is-not-anonymous.html An Analysis of Anonymity in the Bitcoin System]. An Analysis of Anonymity in the Bitcoin System.</ref> This property makes Bitcoin transactions attractive to sellers of illegal products.<ref name="Forbes">Andy Greenberg (20 April 2011). [http://www.forbes.com/forbes/2011/0509/technology-psilocybin-bitcoins-gavin-andresen-crypto-currency.html Crypto Currency]. Forbes Magazine.</ref><ref>{{cite web
|last= Madrigal
|first= Alexis
|title= Libertarian Dream? A Site Where You Buy Drugs With Digital Dollars
|publisher= The Atlantic Monthly
|date= 1 June 2011
|url= https://www.theatlantic.com/technology/archive/2011/06/libertarian-dream-a-site-where-you-buy-drugs-with-digital-dollars/239776/
|accessdate = 5 June 2011
}}</ref>

===Illicit use===

====Cracking====
The cracking organization "LulzSec" accepted donations in bitcoins, having said that the group "needs Bitcoin donations to continue their hacking efforts".<ref name="CNET">{{cite web
|last= Reisinger
|first= Don
|url= https://news.cnet.com/8301-13506_3-20070268-17/senators-target-bitcoin-currency-citing-drug-sales/
|title= Senators target Bitcoin currency, citing drug sales | The Digital Home – CNET News
|publisher= News.cnet.com
|date= 9 June 2011
|accessdate = 22 June 2011
}}</ref><ref>{{cite news
|last= Olson
|first= Parmy
|url= http://blogs.forbes.com/parmyolson/2011/06/06/lulzsec-hackers-posts-sony-dev-source-code-get-7k-donation/
|title= LulzSec Hackers Post Sony Dev. Source Code, Get $7K Donation – Parmy Olson – Disruptors – Forbes
|publisher= Blogs.forbes.com
|date= 6 June 2011
|accessdate = 22 June 2011
}}</ref>

====Silk Road====
[[Silk Road]] is an anonymous black market that uses only the bitcoin.<ref name="npr-06-12-11">
{{Cite news
|url= https://www.npr.org/2011/06/12/137138008/silk-road-not-your-fathers-amazon-com
|date= 12 June 2011
|newspaper= NPR
|title= Silk Road: Not Your Father's Amazon.com
|author= Staff
}}</ref>

In a 2011 letter to Attorney General Eric Holder and the Drug Enforcement Administration, senators Charles Schumer of New York and Joe Manchin of West Virginia called for an investigation into Silk Road and the bitcoin.<ref name="npr-06-12-11"/>
Schumer described the use of bitcoins at Silk Road as a form of money laundering.<ref name="ars-06-08-11"/>

====Botnet mining====
In June 2011, Symantec warned about the possibility of botnets engaging in covert "mining" of bitcoins,<ref>{{Cite web|author=Updated: 17 June 2011 | Translations available: 日本語 |url=http://www.symantec.com/connect/blogs/bitcoin-botnet-mining |title=Bitcoin Botnet Mining | Symantec Connect Community |publisher=Symantec.com |date=17 June 2011 |accessdate = 24 January 2012}}</ref><ref>{{Cite web|url=http://www.zdnet.com/blog/security/researchers-find-malware-rigged-with-bitcoin-miner/8934 |title=Researchers find malware rigged with Bitcoin miner |publisher=ZDNet |date=29 June 2011 |accessdate = 24 January 2012}}</ref> consuming computing cycles, using extra electricity and possibly increasing the temperature of the computer (not associated with [http://snowafter.com Snow Day Calculator]). Later that month, the Australian Broadcasting Corporation caught an employee using the company's servers to generate bitcoins without permission.<ref>{{Cite web|url=http://thenextweb.com/au/2011/06/23/abc-employee-caught-mining-for-bitcoins-on-company-servers/ |title=ABC employee caught mining for Bitcoins on company servers |publisher=The Next Web |date=23 June 2011 |accessdate = 24 January 2012}}</ref> Some malware also uses the parallel processing capabilities of the GPUs built into many modern-day video cards.<ref>{{Cite news |url=https://www.theregister.co.uk/2011/08/16/gpu_bitcoin_brute_forcing/ |title=Malware mints virtual currency using victim's GPU |date=16 August 2011|first=Dan |last=Goodin }}</ref> In mid August 2011, bitcoin miner botnets were found;<ref>{{Cite web|url=http://www.infosecurity-magazine.com/view/20211/researcher-discovers-distributed-bitcoin-cracking-trojan-malware/ |title=Infosecurity – Researcher discovers distributed bitcoin cracking trojan malware |publisher=Infosecurity-magazine.com |date=19 August 2011 |accessdate = 24 January 2012}}</ref> trojans infecting Mac OS X have also been uncovered.<ref>{{Cite web|url=http://www.techworld.com.au/article/405849/mac_os_x_trojan_steals_processing_power_produce_bitcoins |title=Mac OS X Trojan steals processing power to produce Bitcoins – sophos, security, malware, Intego – Vulnerabilities – Security |publisher=Techworld |date=1 November 2011 |accessdate = 24 January 2012}}</ref>

===Theft and fraud===
On 19 June 2011, a security breach of the Mt.Gox (an acronym for ''M''agic: ''T''he ''G''athering ''O''nline E''x''change, its original purpose) bitcoin exchange caused the price of a bitcoin to briefly drop to US$0.01 on the Mt.Gox exchange (though it remained unaffected on other exchanges) after a hacker allegedly used credentials from a Mt.Gox auditor's compromised computer to illegally transfer a large number of bitcoins to him- or herself and sell them all, creating a massive "ask" order at any price. Within minutes the price rebounded to over $15 before Mt.Gox shut down their exchange and cancelled all trades that happened during the hacking period.<ref>[https://mtgox.com/press_release_20110630.html Clarification of Mt Gox Compromised Accounts and Major Bitcoin Sell-Off]</ref><ref>[https://www.youtube.com/watch?v=T1X6qQt9ONg YouTube. Bitcoin Report]</ref> The exchange rate of bitcoins quickly returned to near pre-crash values.<ref name="mick">Jason Mick, 19 June 2011, [http://www.dailytech.com/Inside+the+MegaHack+of+Bitcoin+the+Full+Story/article21942.htm Inside the Mega-Hack of Bitcoin: the Full Story], DailyTech</ref><ref>Timothy B. Lee, 19 June 2011, [https://arstechnica.com/tech-policy/news/2011/06/bitcoin-price-plummets-on-compromised-exchange.ars Bitcoin prices plummet on hacked exchange], Ars Technica</ref><ref>Mark Karpeles, 20 June 2011, [https://support.mtgox.com/entries/20208066-huge-bitcoin-sell-off-due-to-a-compromised-account-rollback Huge Bitcoin sell off due to a compromised account – rollback], Mt.Gox Support</ref><ref name="register1">{{Cite news
|title= Bitcoin collapses on malicious trade – Mt Gox scrambling to raise the Titanic
|url= https://www.theregister.co.uk/2011/06/19/bitcoin_values_collapse_again/
|date= 19 June 2011
|author= Chirgwin, Richard
|publisher= The Register
}}</ref> Accounts with the equivalent of more than USD 8,750,000 were affected.<ref name="mick" />

In July 2011, The operator of Bitomat, the third largest bitcoin exchange, announced that he lost access to his wallet.dat file with about 17,000 bitcoins (roughly equivalent to USD 220,000 at that time). He announced that he would sell the service for the missing amount, aiming to use funds from the sale to refund his customers.<ref>[http://siliconangle.com/blog/2011/08/01/third-largest-bitcoin-exchange-bitomat-lost-their-wallet-over-17000-bitcoins-missing/ Third Largest Bitcoin Exchange Bitomat Lost Their Wallet, Over 17,000 Bitcoins Missing]. SiliconAngle</ref>

In August 2011, MyBitcoin, one of the popular Bitcoin transaction processors, declared that it was hacked, which resulted in it being shut down with paying 49% on customer deposits leaving more than 78,000 BitCoins (roughly equivalent to USD 800,000 at that time) unaccounted for.<ref>[http://betabeat.com/2011/08/mybitcoin-spokesman-finally-comes-forward-what-did-you-think-we-did-after-the-hack-we-got-shitfaced/ MyBitcoin Spokesman Finally Comes Forward: “What Did You Think We Did After the Hack? We Got Shitfaced”]. BetaBeat</ref><ref>[http://betabeat.com/2011/08/search-for-owners-of-mybitcoin-loses-steam/ Search for Owners of MyBitcoin Loses Steam]. BetaBeat</ref>

In early August 2012, a lawsuit was filed in San Francisco court against Bitcoinica, claiming about USD 460,000 from the company. Bitcoinica was hacked twice in 2012, which led to allegations of neglecting the safety of customers' money and cheating them out of withdrawal requests.<ref>[https://arstechnica.com/tech-policy/2012/08/bitcoinica-users-sue-for-460k-in-lost-bitcoins/ Bitcoinica users sue for $460k in lost Bitcoins]. Arstechnica</ref><ref>[https://spectrum.ieee.org/tech-talk/computing/networks/first-bitcoin-lawsuit-filed-in-san-francisco First Bitcoin Lawsuit Filed In San Francisco]. IEEE Spectrum</ref>

In late August 2012, Bitcoin Savings and Trust was shut down by the owner, allegedly leaving around $5.6 million in debts; this led to allegations of the operation being a Ponzi scheme.<ref>{{Cite web|title=Bitcoin ponzi scheme – investors lose $5 million USD in online hedge fund|url=https://rt.com/usa/news/investors-currency-digital-fund-868/|publisher=RT}}</ref><ref>{{Cite web|last=Jeffries|first=Adrianne|title=Suspected multi-million dollar Bitcoin pyramid scheme shuts down, investors revolt|url=http://www.theverge.com/2012/8/27/3271637/bitcoin-savings-trust-pyramid-scheme-shuts-down|publisher=The Verge}}</ref><ref>{{Cite web|last=Mick|first=Jason|title="Pirateat40" Makes Off $5.6M USD in Bitcoin From Pyramid Scheme|url=http://www.dailytech.com/Pirateat40+Makes+Off+56M+USD+in+BitCoins+From+Pyramid+Scheme/article25538.htm|publisher=DailyTech}}</ref><ref>[https://pandodaily.com/2012/08/31/bitcoin-how-a-virtual-currency-became-real-with-a-5-6m-fraud/ Bitcoin: How a Virtual Currency Became Real with a $5.6M Fraud]. PandoDaily</ref> In September 2012, it was reported that U.S. Securities and Exchange Commission has started an investigation on the case.<ref>[http://blogs.telegraph.co.uk/technology/willardfoxton2/100007836/bitcoin-pirate-scandal-sec-steps-in-amid-allegations-that-the-whole-thing-was-a-ponzi-scheme/ Bitcoin 'Pirate' scandal: SEC steps in amid allegations that the whole thing was a Ponzi scheme ]. The Telegraph</ref>

In September 2012, Bitfloor bitcoin exchange also reported being hacked, with 24,000 bitcoins (roughly equivalent to USD 250,000) stolen. As a result, Bitfloor suspended operations.<ref>[http://www.bbc.co.uk/news/technology-19486695 Bitcoin theft causes Bitfloor exchange to go offline]. BBC</ref><ref>[http://www.theverge.com/2012/9/5/3293375/bitfloor-bitcoin-exchange-suspended-theft Bitcoin exchange BitFloor suspends operations after $250,000 theft bitcoin exchange BitFloor suspends operations after $250,000 theft]. The Verge</ref> The same month, Bitfloor resumed operations, with its founder saying that he reported the theft to FBI, and that he is planning to repay the victims, though the time frame for such repayment is unclear.<ref>[http://www.pcworld.com/article/2010586/bitcoin-exchange-back-online-after-hack.html?tk=rel_news Bitcoin exchange back online after hack]. PCWorld</ref>

===Taxation===
In September 2012, the Intra-European Organization of Tax Administrations (IOTA), in Tbilisi, Georgia, held a workshop titled "Auditing Individuals and Legal Entities in the Use of e-Money". The workshop was attended by representatives from 23 countries.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Jerry Taylor, IOTA's technical taxation expert, said, "There's an awful lot happening on the Internet environment which is fascinating at the moment and introducing new challenges for auditors when it comes to virtual currency."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Bitcoin was mentioned during the workshop.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

Matthew Elias, founder of the [[Cryptocurrency Legal Advocacy Group]] (CLAG) published "Staying Between the Lines: A Survey of U.S. Income Taxation and its Ramifications on Cryptocurrencies", which discusses "the taxability of cryptocurrencies such as Bitcoin".<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> CLAG "stressed the importance for taxpayers to determine on their own whether taxes are due on a Bitcoin-related transaction based on whether one has "experienced a realization event."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Such examples are "when a taxpayer has provided a service in exchange for Bitcoins, a realization event has probably occurred, and any gain or loss would likely be calculated using fair market values for the service provided."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

[[Peter Vessenes]], [[Bitcoin Foundation|Bitcoin Foundation's]] executive director, said, since the foundation is trying to pay for everything in bitcoins, including salaries, "How do we W-2 someone for their Bitcoins? Do we mark-to-market every time a transfer happens? Payroll companies cringe."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> The Bitcoin Foundation hopes "to push for solid guidance about its legal and tax treatment." [[Patrick Murck]], legal counsel for the Bitcoin Foundation, said he would like "to help regulators understand the technology better so they can make better decisions."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Murck said, "Bitcoin has the potential to become much more than a niche currency, but it needs the guidance and understanding of regulators." and "The full potential of Bitcoin could be realized through clearer guidelines and a better understanding by financial and tax regulators." and "Part of making that happen is to talk to regulators, the IRS, and tax professionals and helping them understand that Bitcoin is not this nefarious thing, it's just software, it's a community, and there's nothing inherently nefarious about either of those things."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

==See Also==
* [[Introduction]]
* [[Getting started]]
* [[Using_Bitcoin|Detailed tutorial]]
* [[FAQ]]
* [https://www.weusecoins.com What Is Bitcoin?]
* [https://www.bitcoinmining.com What Is Bitcoin Mining?]

==Where to check Bitcoin price==
[https://www.coingecko.com/en/coins/bitcoin Coingecko BTC price]
 
[https://coinriders.com/coin/bitcoin Coinriders BTC price]
 
[https://www.livecoinwatch.com/price/Bitcoin-BTC Livecoinwatch BTC price]

==Where to find Bitcoin Atm near me==

[https://paxful.com/atm Paxful]
 
[https://coinatmradar.com/ coinatmradar.]

==References==
<references />

[[Category:Digital currencies]]
{{wp}}{{p-move}}{{good}}
[[es:Bitcoin]][[de:Bitcoin]]

Bitcoin

2026-02-03T06:40:45Z

NotATether: Remove bitcoin address

'''Bitcoin''' is a decentralized [[digital currency]] created by an unknown person or group of people under the name [[Satoshi Nakamoto]] and released as open-source software in 2009. It does not rely on a central server to process transactions or store funds. There are a maximum of 2,099,999,997,690,000 bitcoin elements (called satoshis, the unit has been named in collective homage to the original creator), which are currently most commonly measured in units of 100,000,000 known as BTC. There will only ever be 21 million bitcoin (BTC) to ever be created.

{{As of|January 2018}}, it is the most widely used alternative currency,<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph">{{cite web|title=Quantitative Analysis of the Full Bitcoin Transaction Graph|url=https://eprint.iacr.org/2012/584.pdf|publisher=Cryptology ePrint Archive|accessdate=18 October 2012|author=Ron Dorit|coauthors=Adi Shamir|page=17|quote=The Bitcoin system is the best known and most widely used alternative payment scheme,...}}</ref><ref name="Cryptocurrency Market Capitalization">{{Cite web|title=Coinmarketcap.com|url=https://coinmarketcap.com/}}</ref> now with the total market cap around 250 billion US dollars.<ref>{{cite web|title=Market Capitalization|url=https://coinmarketcap.com/currencies/bitcoin/|publisher=Coinmarketcap.com|accessdate=10 January 2018}}</ref>

Bitcoin has no central issuer; instead, the peer-to-peer network regulates bitcoins, transactions and issuance according to consensus in network software. These transactions are verified by network nodes through the use of cryptography and recorded in a public distributed ledger called a blockchain.

Bitcoins are issued to various nodes that verify transactions through computing power;
it is established that there will be a limited and scheduled release of no more than BTC 21 million worth of coins, which will be fully issued by the year 2140.

Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoins as payment. Research produced by the University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using Bitcoin.

Internationally, bitcoins can be exchanged and managed through various websites and [[software]] along with physical banknotes and coins.<ref>{{Cite web|title=Physical Bitcoins by Casascius|url=https://www.casascius.com/|publisher=Casascius Coins|accessdate=29 September 2012}}</ref><ref>{{Cite web|title=Bitbills|url=http://www.bitbills.com/|publisher=Bitbills|accessdate=29 September 2012}}</ref>

==History==
{{main|History}}

A cryptographic system for untraceable payments was first described by David Chaum in 1982.<ref>[http://blog.koehntopp.de/uploads/Chaum.BlindSigForPayment.1982.PDF David Chaum, Blind signatures for untraceable payments], Advances in Cryptology - Crypto '82, Springer-Verlag (1983), 199–203.</ref> In 1990 Chaum extended this system to create the first cryptographic anonymous electronic cash system.,<ref>{{cite journal|journal=Lecture Notes in Computer Science|last1=Chaum|first1=David|last2=Fiat|first2=Amos|last3=Naor|first3=Moni|title=Untraceable Electronic Cash|url=http://blog.koehntopp.de/uploads/chaum_fiat_naor_ecash.pdf}}</ref> which became known as ecash.
<ref>{{cite web|url=https://www.wired.com/wired/archive/2.12/emoney.html|publisher=Wired|title=E-Money (That's What I Want)|date=1994–2012|author=Steven Levy}}</ref> In 1998 [[Wei Dai]] published a description of an anonymous, distributed electronic cash system which he called "b-money".<ref>{{cite web|title=B-Money|url=http://www.weidai.com/bmoney.txt|author=Wei Dai|year=1998}}</ref> Around the same time, Nick Szabo created ''bit gold''.<ref>{{cite web|url=https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0|title=Bitcoin: The Cryptoanarchists’ Answer to Cash|publisher=IEEE Spectrum|quote=Around the same time, Nick Szabo, a computer scientist who now blogs about law and the history of money, was one of the first to imagine a new digital currency from the ground up. Although many consider his scheme, which he calls “bit gold,” to be a precursor to Bitcoin}}</ref><ref name="bitgold">{{cite web|title=Bit gold|url=https://unenumerated.blogspot.co.uk/2005/12/bit-gold.html|author=Nick Szabo|quote=My proposal for bit gold is based on computing a string of bits from a string of challenge bits, using functions called variously "client puzzle function," "proof of work function," or "secure benchmark function.". The resulting string of bits is the proof of work.... The last-created string of bit gold provides the challenge bits for the next-created string.}}</ref> Like Bitcoin, ''Bit gold'' was a currency system where users would compete to solve a [[proof of work]] function, with solutions being cryptographically chained together and published via a distributed property title registry. A variant of ''Bit gold'', called ''Reusable Proofs of Work'', was implemented by Hal Finney.<ref name="bitgold"/>

In 2008, Satoshi Nakamoto published a [[Bitcoin_white_paper|paper]]<ref name="whitepaper">{{cite web
|last= Nakamoto
|first= Satoshi
|title= Bitcoin: A Peer-to-Peer Electronic Cash System
|url= http://www.cs.kent.edu/~JAVED/class-P2P12F/papers-2012/PAPER2012-p2p-bitcoin-satoshinakamoto.pdf
|accessdate = 14 December 2010
|date= 24 May 2009
|postscript=
}}</ref><ref>{{cite web
|url= https://article.gmane.org/gmane.comp.encryption.general/12588/
|title= Bitcoin P2P e-cash paper
}}</ref> on The Cryptography Mailing list at metzdowd.com<ref>[https://www.mail-archive.com/search?l=cryptography@metzdowd.com&q=from:%22Satoshi+Nakamoto%22 Satoshi's posts to Cryptography mailing list]</ref> describing the Bitcoin protocol.

The Bitcoin network came into existence on 3 January 2009 with the release of the first Bitcoin client, [[wxBitcoin]], and the issuance of the first bitcoins.<ref>{{cite web |title=Block 0 – Bitcoin Block Explorer |url=https://blockexplorer.com/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f }}</ref><ref>{{cite web |url=https://www.mail-archive.com/cryptography@metzdowd.com/msg10142.html |title=Bitcoin v0.1 released}}</ref><ref>{{cite web |url=https://sourceforge.net/news/?group_id=244765 |title=SourceForge.net: Bitcoin}}</ref>
A year after, the initial exchange rates for Bitcoin were set by individuals on the bitcointalk forums.{{Citation needed|date=October 2012}} The most significant transaction involved a BTC 10,000 pizza.<ref>{{cite web|title=The Rise and Fall of Bitcoin|url=https://www.wired.com/magazine/2011/11/mf_bitcoin/|publisher=Wired|accessdate=13 October 2012}}</ref>
Today, the majority of bitcoin exchanges occur on the [[Bitstamp]] bitcoin exchange.<ref>{{cite web | title = Exchange volume distribution | work = by market | publisher = [[Bitcoin Charts]] | date = 15 April 2014 | url = https://bitcoincharts.com/charts/volumepie/ | accessdate = 15 April 2014 }}</ref>

In 2011, Wikileaks,<ref>{{cite news
|last= Greenberg
|first= Andy
|url= http://blogs.forbes.com/andygreenberg/2011/06/14/wikileaks-asks-for-anonymous-bitcoin-donations/
|title= WikiLeaks Asks For Anonymous Bitcoin Donations – Andy Greenberg – The Firewall – Forbes
|publisher= Blogs.forbes.com
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> [[Freenet]],<ref>{{cite web
|url= https://freenetproject.org/donate.html
|title= /donate
|publisher= The Freenet Project
|date=
|accessdate = 22 June 2011
}}</ref> Singularity Institute,<ref>[http://singinst.org/donate/ SIAI donation page]</ref> Internet Archive,<ref>[https://www.archive.org/donate/index.php Internet Archive donation page]</ref> Free Software Foundation<ref>[https://my.fsf.org/donate/other/ Other ways to donate]</ref> and others, began [[Receiving_donations_with_bitcoin|to accept donations in bitcoins]]. The Electronic Frontier Foundation did so for a while but has since stopped, citing concerns about a lack of legal precedent about new currency systems, and because they "generally don't endorse any type of product or service".<ref>{{cite web
|url= https://www.eff.org/deeplinks/2011/06/eff-and-bitcoin
|title= EFF and Bitcoin | Electronic Frontier Foundation
|publisher= Eff.org
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> Some small businesses had started to adopt Bitcoin. LaCie, a public company, accepts bitcoins for its Wuala service.<ref>{{Cite web|url=http://www.wuala.com/en/bitcoin |title=Secure Online Storage – Backup. Sync. Share. Access Everywhere |publisher=Wuala |date= |accessdate = 24 January 2012}}</ref>

In 2012, BitPay reports of having over 1000 merchants accepting bitcoins under its payment processing service.<ref>{{cite web|title=BitPay Signs 1,000 Merchants to Accept Bitcoin Payments|url=http://www.americanbanker.com/issues/177_176/bitpay-signs-1000-merchants-to-accept-bitcoin-payments-1052538-1.html|publisher=American Banker|accessdate=12 October 2012}}</ref>

==Administration==
Bitcoin is administered through a decentralized peer-to-peer network.<ref name="whitepaper"/> Cryptographic technologies and the peer-to-peer network of computing power enables users to make and verify irreversible, instant online bitcoin payments, without an obligation to trust and use centralized banking institutions and authorities. Dispute resolution services are not made directly available. Instead it is left to the users to verify and trust the parties they are sending money to through their choice of methods.

Bitcoins are issued according to rules agreed to by the majority of the computing power within the Bitcoin network. The core rules describing the predictable issuance of bitcoins to its verifying servers, a voluntary and competitive transaction fee system and the hard limit of no more than BTC 21 million issued in total.<ref name="whitepaper"/>

Bitcoin does not require a central bank, State,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/3
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> or incorporated backers.

==Services==
{{main|Wallet}}

Bitcoins are sent and received through software and websites called wallets. They send and confirm transactions to the network through Bitcoin addresses, the identifiers for users' Bitcoin wallets within the network.<ref name="whitepaper"/>

===Bitcoin addresses===
{{main|Address}}

Payments are made to Bitcoin "addresses": human-readable strings of numbers and letters around 33 characters in length, always beginning with the digit 1 or 3. However, newer "[[Segregated Witness|Segwit]]" addresses begin with bc1 and contain entirely numbers and lowercase letters.

Users obtain new Bitcoin addresses from their Bitcoin software. Creating a new address can be a completely offline process and require no communication with the Bitcoin network. Web services usually generate a new Bitcoin address for every user, allowing them to have their custom deposit addresses, but sometimes this is not the case.

===Transaction fees===
{{main|Transaction fees}}
Transaction fees may be included with any transfer of bitcoins. While it's technically possible to send a transaction with zero fee, {{as of|2017|lc=on}} it's highly unlikely that one of these transactions confirms in a realistic amount of time, causing most nodes on the network to drop it. For transactions which consume or produce many outputs (and therefore have a large data size), higher transaction fees are usually expected.

===Confirmations===
{{main|Confirmation}}

The network's software confirms a transaction when it records it in a block. Further blocks of transactions confirm it even further. After six confirmations/blocks, a transaction is confirmed beyond reasonable doubt.

The network must store the whole transaction history inside the blockchain, which grows constantly as new records are added and never removed. Nakamoto conceived that as the database became larger, users would desire applications for Bitcoin that didn't store the entire database on their computer. To enable this, the blockchain uses a [[merkle tree]] to organize the transaction records in such a way that client software can locally delete portions of its own database it knows it will never need, such as earlier transaction records of bitcoins that have changed ownership multiple times.

==Economics==

===Initial distribution===

Bitcoin has no centralized issuing authority.<ref name="ars-06-08-11">
{{Cite news
|first= Thomas
|last= Lowenthal
|title= Bitcoin: inside the encrypted, peer-to-peer digital currency
|newspaper= Ars Technica
|date= 8 June 2011
|url= https://arstechnica.com/tech-policy/news/2011/06/bitcoin-inside-the-encrypted-peer-to-peer-currency.ars
}}</ref><ref>{{cite news
|author= Sponsored by
|url= http://www.economist.com/blogs/babbage/2011/06/virtual-currency
|title= Virtual currency: Bits and bob
|publisher= The Economist
|date=
|accessdate = 22 June 2011
}}</ref><ref>{{cite web
|last= Geere
|first= Duncan
|url= https://www.wired.co.uk/news/archive/2011-05/16/bitcoin-p2p-currency
|title= Peer-to-peer currency Bitcoin sidesteps financial institutions (Wired UK)
|publisher= Wired.co.uk
|date=
|accessdate = 22 June 2011
}}</ref> The network is programmed to increase the money supply as a geometric series until the total number of bitcoins reaches 21 million.<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph"/> {{As of|2012|10}} slightly over 10 million of the total BTC 21 million had been created; the current total number created is available online.<ref>{{cite web
|title= Total Number of Bitcoins in Existence
|url= https://blockexplorer.com/q/totalbc
|work= Bitcoin Block Explorer
|accessdate = 3 October 2012
}}</ref> By 2013 half of the total supply will have been generated, and by 2017, three-quarters will have been generated. To ensure sufficient granularity of the [[money supply]], clients can divide each BTC unit down to eight decimal places (a total of 2.1 × 1015 or 2.1 quadrillion units).<ref name="lwn">{{Cite news
|author= Nathan Willis
|date= 10 November 2010
|title= Bitcoin: Virtual money created by CPU cycles
|publisher= LWN.net
|url= https://lwn.net/Articles/414452/
}}</ref>

The network {{As of|2012|lc=on}} required over one million times more work for confirming a block and receiving an award (BTC 25 {{As of|2012|2|lc=on}}) than when the first blocks were confirmed.
The difficulty is automatically adjusted every 2016 blocks based on the time taken to find the previous 2016 blocks such that one block is created roughly every 10 minutes.

Those who chose to put computational and electrical resources toward mining early on had a greater chance at receiving awards for block generations. This served to make available enough processing power to process blocks. Indeed, without miners there are no transactions and the bitcoin economy comes to a halt.

===Exchange rate===
Prices fluctuate relative to goods and services more than more widely accepted currencies;
the price of a bitcoin is not static.

In August 2012, 1 bitcoin traded at around US$10.00. Taking into account the total number of bitcoins mined, the monetary base of the Bitcoin network stands at over USD 110 million.<ref>[http://www.bitcoinwatch.com/ http://www.bitcoinwatch.com/] Bitcoin statistics</ref>

== Anonymity ==
{{main|Anonymity & Security}}

=== Transactions ===

While using bitcoins is an excellent way to make your purchases, donations, and p2p payments without losing money through inflated transaction fees, transactions are never truly anonymous. Buying bitcoin you pass identification, Bitcoin transactions are stored publicly and permanently on the network, which means anyone can see the balance and transactions of any Bitcoin address. Bitcoin activities are recorded and available publicly via the [[blockchain]], a comprehensive database which keeps a record of Bitcoin transactions.

=== Buying/selling bitcoins ===

All exchange companies require the user to scan ID documents, and large transactions must be reported to the proper governmental authority.

This means that a third party with an interest in tracking your activities can use your visible balance and ID information as a basis from which to track your future transactions or to study previous activity. In short, you have compromised your [[security]] and [[privacy]].

In addition to conventional exchanges there are also peer-to-peer exchanges. Peer to peer exchanges will often not collect KYC and identity information directly from users, instead they let the users handle KYC amongst themselves. These can often be a better alternative for those looking to purchase bitcoins quickly and without KYC delay.

=== Mixing services ===

[http://anonymity.co.in/mixing_services.html Mixing services] are used to avoid compromising of privacy and security. Mixing services provide to periodically exchange your bitcoins for different ones which cannot be associated with the original owner.

== Security ==
{{seealso|Weaknesses}}

In the history of Bitcoin, there have been a few [[incidents]], caused by problematic as well as malicious transactions. In the worst such incident, and the only one of its type, a person was able to pretend that he had a practically infinite supply of bitcoins, for almost 9 hours.

Bitcoin relies, among other things, on [https://en.wikipedia.org/wiki/Public-key_cryptography public key cryptography] and thus may be vulnerable to [https://en.wikipedia.org/wiki/Elliptic_curve_cryptography#Quantum_computing_attacks quantum computing attacks] if and when practical quantum computers can be constructed.

If multiple different software packages, whose usage becomes widespread on the Bitcoin network, disagree on the protocol and the rules for transactions, this could potentially cause a fork in the block chain with each faction of users being able to accept only their own version of the history of transactions. This could influence the price of bitcoins.

A global, organized campaign against the currency or the software could also influence the demand for bitcoins, and thus the exchange price.

==Bitcoin mining==
{{main|Mining}}

Bitcoin mining nodes are responsible for managing the Bitcoin network.

Bitcoins are awarded to Bitcoin nodes known as "miners" for the solution to a difficult [[proof-of-work]] problem which confirms transactions and prevents double-spending. This incentive, as the Nakamoto white paper describes it, encourages "nodes to support the network, and provides a way to initially distribute coins into circulation, since no central authority issues them."<ref name="whitepaper" />

Nakamoto compared the generation of new coins by expending CPU time and electricity to gold miners expending resources to add gold to circulation.<ref name="whitepaper"/>

[[File:Cryptocurrency Mining Farm.jpg|right|350px|thumb|Iceland is a good location for [[mining]] bitcoins because of the natural cold temperature.]]

===Node operation===

The node software for the Bitcoin network is based on peer-to-peer networking, digital signatures and cryptographic proof to make and verify transactions. Nodes broadcast transactions to the network, which records them in a public record of all transactions called the ''blockchain'' after validating them with a [[proof-of-work|proof-of-work system]].

Satoshi Nakamoto designed the first Bitcoin node and mining software<ref name="processors">{{Cite news
|last= Davis
|first= Joshua
|title= The Crypto-Currency
|url= https://www.wired.com/magazine/2011/11/mf_bitcoin/all
|accessdate = 11 November 2011
|newspaper= Wired Magazine
|date= 10 November 2011
}}</ref> and developed the majority of the first implementation, Bitcoind, from 2007 to mid-2010.<ref name="code_start">{{cite web
|url= https://bitcointalk.org/index.php?topic=13.msg46#msg46
|title= Questions about Bitcoin
|publisher= Bitcoin forum
|date= 10 December 2009
}}</ref>

Node implementations include core software such as Bitcoind/Bitcoin-Qt, [[libbitcoin]], [[cbitcoin]]<ref>{{Cite web|title=cbitcoin|url=https://github.com/MatthewLM/cbitcoin|accessdate=3 October 2012}}</ref> and [[BitCoinJ|bitcoinj]].<ref>{{cite web
|url= https://news.slashdot.org/story/11/03/23/0210207/Google-Engineer-Releases-Open-Source-Bitcoin-Client
|title= Google Engineer Releases Open Source Bitcoin Client
|author= angry tapir, timothy
|date= 23 March 2011
|publisher= Slashdot
|accessdate = 18 May 2011
}}</ref><ref>{{cite web
|url= http://www.javaworld.com/javaworld/jw-01-2012/120110-bitcoin-for-beginners-3.html?page=1
|title= Bitcoin for beginners: The BitcoinJ API
|author= Dirk Merkel
|date= 10 January 2012
|publisher= JavaWorld
|accessdate = 3 August 2012
}}</ref>

Every node in the Bitcoin network collects all the unacknowledged transactions it knows of in a file called a ''block'', which also contains a reference to the previous valid block known to that node. It then appends a [[nonce]] value to this previous block and computes the SHA-256 cryptographic hash of the block and the appended nonce value. The node repeats this process until it adds a nonce that allows for the generation of a hash with a value lower than a specified ''target''. Because computers cannot practically reverse the hash function, finding such a nonce is hard and requires on average a predictable amount of repetitious trial and error. This is where the ''[[proof-of-work]]'' concept comes in to play. When a node finds such a solution, it announces it to the rest of the network. Peers receiving the new solved block validate it by computing the hash and checking that it really starts with the given number of zero bits (i.e., that the hash is within the target). Then they accept it and add it to the chain.

===Mining rewards===
In addition to receiving the pending transactions confirmed in the block, a generating node adds a ''generate'' transaction, which awards new bitcoins to the operator of the node that generated the block. The system sets the payout of this generated transaction according to its defined inflation schedule. The miner that generates a block also receives the fees that users have paid as an incentive to give particular transactions priority for faster confirmation.<ref>[https://www.bitcoinmining.com Bitcoin Mining]</ref>

The network never creates more than a BTC 50 reward per block and this amount will decrease over time towards zero, such that no more than BTC 21 million will ever exist.<ref name="lwn" /> As this payout decreases, the incentive for users to run block-generating nodes is intended to change to earning [[#Transaction fees|transaction fees]].

===Mining pools===
{{main|Pooled mining}}

Bitcoin users often pool computational effort to increase the stability of the collected fees and subsidy they receive.<ref name="We Use Coins Mining">{{cite web|title=About Bitcoin Mining|url=https://www.weusecoins.com/en/mining-guide/|publisher=We Use Coins|accessdate=27 May 2015}}</ref>

===Mining difficulty===
{{main|Difficulty}}

In order to throttle the creation of blocks, the difficulty of generating new blocks is adjusted over time. If mining output increases or decreases, the difficulty increases or decreases accordingly.

The adjustment is done by changing the threshold that a hash is required to be less than. A lower threshold means fewer possible hashes can be accepted, and thus a higher degree of difficulty. The target rate of block generation is one block every 10 minutes, or 2016 blocks every two weeks. Bitcoin changes the difficulty of finding a valid block every 2016 blocks, using the difficulty that would have been most likely to cause the prior 2016 blocks to have taken two weeks to generate, according to the timestamps on the blocks. Technically, this is done by modelling the generation of bitcoins as Poisson process. All nodes perform and enforce the same difficulty calculation.

Difficulty is intended as an automatic stabilizer allowing mining for bitcoins to remain profitable in the long run for the most efficient miners, independently of the fluctuations in demand of the bitcoin in relation to other currencies.

===Mining hardware===
{{main|Mining Hardware Comparison}}

Bitcoins used to be mined through Intel/AMD CPUs. {{As of | 2012}}, mining has gradually moved to [[GPU]] and [[FPGA]] hardware.<ref name="bitcoinmag-butterfly" /> [[Application-specific integrated circuit|ASIC]]-based hardware for bitcoin mining has been announced by several manufacturers who intend to ship products from late 2012 to early 2013.<ref name="bitcoinmag-butterfly">{{Cite web|title=Bitpay Breaks Daily Volume Record with Butterfly ASIC mining release|url=http://bitcoinmagazine.net/bitpay-breaks-daily-volume-record-with-butterfly-asic-mining-release/|publisher=Bitcoin Magazine}}</ref>

==Concerns==

===As an investment===
{{main|Bitcoin as an investment}}

Bitcoin describes itself as an experimental digital currency. Reuben Grinberg has noted that Bitcoin's supporters have argued that bitcoins are neither securities nor investments because they fail to meet the criteria for either category.<ref name="grinberg">{{cite web | url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1817857 | title=Bitcoin: An Innovative Alternative Digital Currency | publisher=SSRN | date=9 December 2011 | accessdate=4 December 2012 | author=Grinberg, Reuben}}</ref> Although it is a virtual currency, some people see it as an investment<ref name="cnbc">{{cite web | url=http://www.cnbc.com/id/45030812/The_Pros_And_Cons_Of_Biting_on_Bitcoins | title=The Pros And Cons Of Biting on Bitcoins | publisher=CNBC | date=23 November 2011 | accessdate=4 December 2012 | author=Gustke, Constance}}</ref> or accuse it of being a form of investment fraud known as a Ponzi scheme.<ref>{{cite web |url=https://www.theregister.co.uk/2011/06/08/bitcoin_under_attack/ |title=US senators draw a bead on Bitcoin |last1=Chirgwin |first1=Richard |date=8 June 2011 |publisher=The Register |accessdate=14 November 2012}}</ref><ref>{{cite web |url=http://uk.reuters.com/article/2012/04/01/uk-traders-bitcoin-idUKBRE8300JL20120401 |title=Bitcoin, the City traders' anarchic new toy |last1=O'Leary |first1=Naomi |date=2 April 2012 |publisher=Reuters |accessdate=14 November 2012}}</ref> A report by the European Central Bank, using the U.S. Securities and Exchange Commission's definition of a Ponzi scheme, found that the use of bitcoins shares some characteristics with Ponzi schemes, but also has characteristics of its own which contradict several common aspects of Ponzi schemes.<ref name="ecbreport">{{cite web | url=http://www.ecb.europa.eu/pub/pdf/other/virtualcurrencyschemes201210en.pdf | title=Virtual Currency Schemes | publisher=European Central Bank | date=October 2012 | accessdate=4 December 2012}}</ref>

===Privacy===
Because transactions are broadcast to the entire network, they are inherently public. Unlike regular banking,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> which preserves customer privacy by keeping transaction records private, loose transactional privacy is accomplished in Bitcoin by using many unique addresses for every wallet while at the same time publishing all transactions. As an example, if Alice sends BTC 123.45 to Bob, the network creates a public record that allows anyone to see that 123.45 has been sent from one address to another. However, unless Alice or Bob make their ownership of these addresses known, it is difficult for anyone else to connect the transaction with them. However, if someone connects an address to a user at any point they could follow back a series of transactions as each participant likely knows who paid them and may disclose that information on request or under duress.

It can be difficult to associate Bitcoin identities with real-life identities.<ref name="An Analysis of Anonymity in the Bitcoin System">Fergal Reid and Martin Harrigan (24 July 2011). [https://anonymity-in-bitcoin.blogspot.com/2011/07/bitcoin-is-not-anonymous.html An Analysis of Anonymity in the Bitcoin System]. An Analysis of Anonymity in the Bitcoin System.</ref> This property makes Bitcoin transactions attractive to sellers of illegal products.<ref name="Forbes">Andy Greenberg (20 April 2011). [http://www.forbes.com/forbes/2011/0509/technology-psilocybin-bitcoins-gavin-andresen-crypto-currency.html Crypto Currency]. Forbes Magazine.</ref><ref>{{cite web
|last= Madrigal
|first= Alexis
|title= Libertarian Dream? A Site Where You Buy Drugs With Digital Dollars
|publisher= The Atlantic Monthly
|date= 1 June 2011
|url= https://www.theatlantic.com/technology/archive/2011/06/libertarian-dream-a-site-where-you-buy-drugs-with-digital-dollars/239776/
|accessdate = 5 June 2011
}}</ref>

===Illicit use===

====Cracking====
The cracking organization "LulzSec" accepted donations in bitcoins, having said that the group "needs Bitcoin donations to continue their hacking efforts".<ref name="CNET">{{cite web
|last= Reisinger
|first= Don
|url= https://news.cnet.com/8301-13506_3-20070268-17/senators-target-bitcoin-currency-citing-drug-sales/
|title= Senators target Bitcoin currency, citing drug sales | The Digital Home – CNET News
|publisher= News.cnet.com
|date= 9 June 2011
|accessdate = 22 June 2011
}}</ref><ref>{{cite news
|last= Olson
|first= Parmy
|url= http://blogs.forbes.com/parmyolson/2011/06/06/lulzsec-hackers-posts-sony-dev-source-code-get-7k-donation/
|title= LulzSec Hackers Post Sony Dev. Source Code, Get $7K Donation – Parmy Olson – Disruptors – Forbes
|publisher= Blogs.forbes.com
|date= 6 June 2011
|accessdate = 22 June 2011
}}</ref>

====Silk Road====
[[Silk Road]] is an anonymous black market that uses only the bitcoin.<ref name="npr-06-12-11">
{{Cite news
|url= https://www.npr.org/2011/06/12/137138008/silk-road-not-your-fathers-amazon-com
|date= 12 June 2011
|newspaper= NPR
|title= Silk Road: Not Your Father's Amazon.com
|author= Staff
}}</ref>

In a 2011 letter to Attorney General Eric Holder and the Drug Enforcement Administration, senators Charles Schumer of New York and Joe Manchin of West Virginia called for an investigation into Silk Road and the bitcoin.<ref name="npr-06-12-11"/>
Schumer described the use of bitcoins at Silk Road as a form of money laundering.<ref name="ars-06-08-11"/>

====Botnet mining====
In June 2011, Symantec warned about the possibility of botnets engaging in covert "mining" of bitcoins,<ref>{{Cite web|author=Updated: 17 June 2011 | Translations available: 日本語 |url=http://www.symantec.com/connect/blogs/bitcoin-botnet-mining |title=Bitcoin Botnet Mining | Symantec Connect Community |publisher=Symantec.com |date=17 June 2011 |accessdate = 24 January 2012}}</ref><ref>{{Cite web|url=http://www.zdnet.com/blog/security/researchers-find-malware-rigged-with-bitcoin-miner/8934 |title=Researchers find malware rigged with Bitcoin miner |publisher=ZDNet |date=29 June 2011 |accessdate = 24 January 2012}}</ref> consuming computing cycles, using extra electricity and possibly increasing the temperature of the computer (not associated with [http://snowafter.com Snow Day Calculator]). Later that month, the Australian Broadcasting Corporation caught an employee using the company's servers to generate bitcoins without permission.<ref>{{Cite web|url=http://thenextweb.com/au/2011/06/23/abc-employee-caught-mining-for-bitcoins-on-company-servers/ |title=ABC employee caught mining for Bitcoins on company servers |publisher=The Next Web |date=23 June 2011 |accessdate = 24 January 2012}}</ref> Some malware also uses the parallel processing capabilities of the GPUs built into many modern-day video cards.<ref>{{Cite news |url=https://www.theregister.co.uk/2011/08/16/gpu_bitcoin_brute_forcing/ |title=Malware mints virtual currency using victim's GPU |date=16 August 2011|first=Dan |last=Goodin }}</ref> In mid August 2011, bitcoin miner botnets were found;<ref>{{Cite web|url=http://www.infosecurity-magazine.com/view/20211/researcher-discovers-distributed-bitcoin-cracking-trojan-malware/ |title=Infosecurity – Researcher discovers distributed bitcoin cracking trojan malware |publisher=Infosecurity-magazine.com |date=19 August 2011 |accessdate = 24 January 2012}}</ref> trojans infecting Mac OS X have also been uncovered.<ref>{{Cite web|url=http://www.techworld.com.au/article/405849/mac_os_x_trojan_steals_processing_power_produce_bitcoins |title=Mac OS X Trojan steals processing power to produce Bitcoins – sophos, security, malware, Intego – Vulnerabilities – Security |publisher=Techworld |date=1 November 2011 |accessdate = 24 January 2012}}</ref>

===Theft and fraud===
On 19 June 2011, a security breach of the Mt.Gox (an acronym for ''M''agic: ''T''he ''G''athering ''O''nline E''x''change, its original purpose) bitcoin exchange caused the price of a bitcoin to briefly drop to US$0.01 on the Mt.Gox exchange (though it remained unaffected on other exchanges) after a hacker allegedly used credentials from a Mt.Gox auditor's compromised computer to illegally transfer a large number of bitcoins to him- or herself and sell them all, creating a massive "ask" order at any price. Within minutes the price rebounded to over $15 before Mt.Gox shut down their exchange and cancelled all trades that happened during the hacking period.<ref>[https://mtgox.com/press_release_20110630.html Clarification of Mt Gox Compromised Accounts and Major Bitcoin Sell-Off]</ref><ref>[https://www.youtube.com/watch?v=T1X6qQt9ONg YouTube. Bitcoin Report]</ref> The exchange rate of bitcoins quickly returned to near pre-crash values.<ref name="mick">Jason Mick, 19 June 2011, [http://www.dailytech.com/Inside+the+MegaHack+of+Bitcoin+the+Full+Story/article21942.htm Inside the Mega-Hack of Bitcoin: the Full Story], DailyTech</ref><ref>Timothy B. Lee, 19 June 2011, [https://arstechnica.com/tech-policy/news/2011/06/bitcoin-price-plummets-on-compromised-exchange.ars Bitcoin prices plummet on hacked exchange], Ars Technica</ref><ref>Mark Karpeles, 20 June 2011, [https://support.mtgox.com/entries/20208066-huge-bitcoin-sell-off-due-to-a-compromised-account-rollback Huge Bitcoin sell off due to a compromised account – rollback], Mt.Gox Support</ref><ref name="register1">{{Cite news
|title= Bitcoin collapses on malicious trade – Mt Gox scrambling to raise the Titanic
|url= https://www.theregister.co.uk/2011/06/19/bitcoin_values_collapse_again/
|date= 19 June 2011
|author= Chirgwin, Richard
|publisher= The Register
}}</ref> Accounts with the equivalent of more than USD 8,750,000 were affected.<ref name="mick" />

In July 2011, The operator of Bitomat, the third largest bitcoin exchange, announced that he lost access to his wallet.dat file with about 17,000 bitcoins (roughly equivalent to USD 220,000 at that time). He announced that he would sell the service for the missing amount, aiming to use funds from the sale to refund his customers.<ref>[http://siliconangle.com/blog/2011/08/01/third-largest-bitcoin-exchange-bitomat-lost-their-wallet-over-17000-bitcoins-missing/ Third Largest Bitcoin Exchange Bitomat Lost Their Wallet, Over 17,000 Bitcoins Missing]. SiliconAngle</ref>

In August 2011, MyBitcoin, one of the popular Bitcoin transaction processors, declared that it was hacked, which resulted in it being shut down with paying 49% on customer deposits leaving more than 78,000 BitCoins (roughly equivalent to USD 800,000 at that time) unaccounted for.<ref>[http://betabeat.com/2011/08/mybitcoin-spokesman-finally-comes-forward-what-did-you-think-we-did-after-the-hack-we-got-shitfaced/ MyBitcoin Spokesman Finally Comes Forward: “What Did You Think We Did After the Hack? We Got Shitfaced”]. BetaBeat</ref><ref>[http://betabeat.com/2011/08/search-for-owners-of-mybitcoin-loses-steam/ Search for Owners of MyBitcoin Loses Steam]. BetaBeat</ref>

In early August 2012, a lawsuit was filed in San Francisco court against Bitcoinica, claiming about USD 460,000 from the company. Bitcoinica was hacked twice in 2012, which led to allegations of neglecting the safety of customers' money and cheating them out of withdrawal requests.<ref>[https://arstechnica.com/tech-policy/2012/08/bitcoinica-users-sue-for-460k-in-lost-bitcoins/ Bitcoinica users sue for $460k in lost Bitcoins]. Arstechnica</ref><ref>[https://spectrum.ieee.org/tech-talk/computing/networks/first-bitcoin-lawsuit-filed-in-san-francisco First Bitcoin Lawsuit Filed In San Francisco]. IEEE Spectrum</ref>

In late August 2012, Bitcoin Savings and Trust was shut down by the owner, allegedly leaving around $5.6 million in debts; this led to allegations of the operation being a Ponzi scheme.<ref>{{Cite web|title=Bitcoin ponzi scheme – investors lose $5 million USD in online hedge fund|url=https://rt.com/usa/news/investors-currency-digital-fund-868/|publisher=RT}}</ref><ref>{{Cite web|last=Jeffries|first=Adrianne|title=Suspected multi-million dollar Bitcoin pyramid scheme shuts down, investors revolt|url=http://www.theverge.com/2012/8/27/3271637/bitcoin-savings-trust-pyramid-scheme-shuts-down|publisher=The Verge}}</ref><ref>{{Cite web|last=Mick|first=Jason|title="Pirateat40" Makes Off $5.6M USD in Bitcoin From Pyramid Scheme|url=http://www.dailytech.com/Pirateat40+Makes+Off+56M+USD+in+BitCoins+From+Pyramid+Scheme/article25538.htm|publisher=DailyTech}}</ref><ref>[https://pandodaily.com/2012/08/31/bitcoin-how-a-virtual-currency-became-real-with-a-5-6m-fraud/ Bitcoin: How a Virtual Currency Became Real with a $5.6M Fraud]. PandoDaily</ref> In September 2012, it was reported that U.S. Securities and Exchange Commission has started an investigation on the case.<ref>[http://blogs.telegraph.co.uk/technology/willardfoxton2/100007836/bitcoin-pirate-scandal-sec-steps-in-amid-allegations-that-the-whole-thing-was-a-ponzi-scheme/ Bitcoin 'Pirate' scandal: SEC steps in amid allegations that the whole thing was a Ponzi scheme ]. The Telegraph</ref>

In September 2012, Bitfloor bitcoin exchange also reported being hacked, with 24,000 bitcoins (roughly equivalent to USD 250,000) stolen. As a result, Bitfloor suspended operations.<ref>[http://www.bbc.co.uk/news/technology-19486695 Bitcoin theft causes Bitfloor exchange to go offline]. BBC</ref><ref>[http://www.theverge.com/2012/9/5/3293375/bitfloor-bitcoin-exchange-suspended-theft Bitcoin exchange BitFloor suspends operations after $250,000 theft bitcoin exchange BitFloor suspends operations after $250,000 theft]. The Verge</ref> The same month, Bitfloor resumed operations, with its founder saying that he reported the theft to FBI, and that he is planning to repay the victims, though the time frame for such repayment is unclear.<ref>[http://www.pcworld.com/article/2010586/bitcoin-exchange-back-online-after-hack.html?tk=rel_news Bitcoin exchange back online after hack]. PCWorld</ref>

===Taxation===
In September 2012, the Intra-European Organization of Tax Administrations (IOTA), in Tbilisi, Georgia, held a workshop titled "Auditing Individuals and Legal Entities in the Use of e-Money". The workshop was attended by representatives from 23 countries.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Jerry Taylor, IOTA's technical taxation expert, said, "There's an awful lot happening on the Internet environment which is fascinating at the moment and introducing new challenges for auditors when it comes to virtual currency."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Bitcoin was mentioned during the workshop.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

Matthew Elias, founder of the [[Cryptocurrency Legal Advocacy Group]] (CLAG) published "Staying Between the Lines: A Survey of U.S. Income Taxation and its Ramifications on Cryptocurrencies", which discusses "the taxability of cryptocurrencies such as Bitcoin".<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> CLAG "stressed the importance for taxpayers to determine on their own whether taxes are due on a Bitcoin-related transaction based on whether one has "experienced a realization event."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Such examples are "when a taxpayer has provided a service in exchange for Bitcoins, a realization event has probably occurred, and any gain or loss would likely be calculated using fair market values for the service provided."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

[[Peter Vessenes]], [[Bitcoin Foundation|Bitcoin Foundation's]] executive director, said, since the foundation is trying to pay for everything in bitcoins, including salaries, "How do we W-2 someone for their Bitcoins? Do we mark-to-market every time a transfer happens? Payroll companies cringe."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> The Bitcoin Foundation hopes "to push for solid guidance about its legal and tax treatment." [[Patrick Murck]], legal counsel for the Bitcoin Foundation, said he would like "to help regulators understand the technology better so they can make better decisions."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Murck said, "Bitcoin has the potential to become much more than a niche currency, but it needs the guidance and understanding of regulators." and "The full potential of Bitcoin could be realized through clearer guidelines and a better understanding by financial and tax regulators." and "Part of making that happen is to talk to regulators, the IRS, and tax professionals and helping them understand that Bitcoin is not this nefarious thing, it's just software, it's a community, and there's nothing inherently nefarious about either of those things."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

==See Also==
* [[Introduction]]
* [[Getting started]]
* [[Using_Bitcoin|Detailed tutorial]]
* [[FAQ]]
* [https://www.weusecoins.com What Is Bitcoin?]
* [https://www.bitcoinmining.com What Is Bitcoin Mining?]

==Where to check Bitcoin price==
[https://www.coingecko.com/en/coins/bitcoin Coingecko BTC price]
 
[https://coinriders.com/coin/bitcoin Coinriders BTC price]
 
[https://www.livecoinwatch.com/price/Bitcoin-BTC Livecoinwatch BTC price]

==Where to find Bitcoin Atm near me==

[https://paxful.com/atm Paxful]
 
[https://coinatmradar.com/ coinatmradar.]

==References==
<references />

[[Category:Digital currencies]]
{{wp}}{{p-move}}{{good}}
[[es:Bitcoin]][[de:Bitcoin]]

Yobit

2026-01-09T16:29:13Z

NotATether: move the dot at the end

'''YoBit''' (also stylized as '''Yobit''' or '''YoBit.net''') is a centralized cryptocurrency exchange founded in 2014. It has a very poor standing among the Bitcoin community, with a reputation of stuck deposits/withdrawals and low-quality customer support.

The platform is registered in Panama and operated by a group of anonymous developers, and is an unregulated exchange with low transparency regarding ownership, team, and security practices.

A brief list of features of this exchange follows.

* No mandatory [[KYC]]
* Extremely large number of trading pairs, however, most of these are dead coins which are perpetually stuck in maintenance mode
* 0.2% trading fee (maker/taker), however, many coins have a high or variable withdraw fee
* Limited support for USD and RUB (via third-party services like AdvCash, Perfect Money, etc.)
* InvestBox (staking-like), YoPony game, free coins campaigns, IEO/ICO listings, virtual mining (VMining)

===Reputation===

This platform has a very bad reputation on Bitcointalk<ref>https://bitcointalk.org/index.php?topic=5133809.0</ref>, primarily due to the signature campaign which they managed in which users were encouraged to write up to 20 posts per day. At one point, the Yobit signature campaign was temporarily banned, with dozens of forum members in the campaign handed temporary bans for spamming. <ref>https://bitcointalk.org/index.php?topic=5133809.msg50727083#msg50727083</ref>

===External links===
* [https://yobit.net/ Official website]

===References===

[[Category:Exchanges]]
[[Category:Centralized exchanges]]

Yobit

2026-01-09T16:28:39Z

NotATether: Expand the page beyond a stub

'''YoBit''' (also stylized as '''Yobit''' or '''YoBit.net''') is a centralized cryptocurrency exchange founded in 2014. It has a very poor standing among the Bitcoin community, with a reputation of stuck deposits/withdrawals and low-quality customer support.

The platform is registered in Panama and operated by a group of anonymous developers, and is an unregulated exchange with low transparency regarding ownership, team, and security practices.

A brief list of features of this exchange follows.

* No mandatory [[KYC]]
* Extremely large number of trading pairs, however, most of these are dead coins which are perpetually stuck in maintenance mode
* 0.2% trading fee (maker/taker), however, many coins have a high or variable withdraw fee
* Limited support for USD and RUB (via third-party services like AdvCash, Perfect Money, etc.)
* InvestBox (staking-like), YoPony game, free coins campaigns, IEO/ICO listings, virtual mining (VMining)

===Reputation===

This platform has a very bad reputation on Bitcointalk<ref>https://bitcointalk.org/index.php?topic=5133809.0</ref>, primarily due to the signature campaign which they managed in which users were encouraged to write up to 20 posts per day. At one point, the Yobit signature campaign was temporarily banned, with dozens of forum members in the campaign handed temporary bans for spamming <ref>https://bitcointalk.org/index.php?topic=5133809.msg50727083#msg50727083</ref>.

===External links===
* [https://yobit.net/ Official website]

===References===

[[Category:Exchanges]]
[[Category:Centralized exchanges]]

User:NotATether

2026-01-08T14:21:25Z

NotATether: moderation policy

NotATether on Bitcoin Wiki (https://notatether.com) and Bitcointalk (https://bitcointalk.org/index.php?action=profile;u=2739424)

To contact me, use my personal email <ali at notatether dot com> or on Bitcointalk with the same username. The admin email is for site inquiries only.

Tips: bc1q4djl6pxt90nfs8fufdul26ufxukxxrczsfjj0h

'''I can whitelist your Bitcoin Wiki account for editing.''' See [[Bitcoin Wiki:Editing privileges|this page]] for details. Do not send me attachments or ''your email will be blocked'', as those are usually used to spread malware.

== Moderation Policy ==

Generally, edits to your own talk pages are approved as long as they don't contain links to malware/scams/phishing and so on.

Edits to other pages are usually approved unless they are spammy in nature.

Talk:Bitcoin API Services

2026-01-02T16:58:05Z

NotATether: Propose delete or merge

== Delete or merge? ==

It might make sense to merge this page with some larger page, given this service never seemed to have been launched ever, and it's basically being used as an advertising board for people to advertise their APIs.

--[[User:NotATether|NotATether]] ([[User talk:NotATether|talk]]) 16:57, 2 January 2026 (UTC)

Bitcoin API Services

2026-01-02T16:56:34Z

NotATether: Add inactivity notice

Bitcoin API Services makes accepting Bitcoin payments as easy as handling HTTP requests.

Unlike most online payment notification services, payments are not actually sent to Bitcoin API Services, so there is no need of entrusting someone else with your wallet, or letting someone else manage one for you. Payments go directly from a customer to the merchant

Bitcoin API Services also delivers HTTP POST notifications about Bitcoin exchange rates, and difficulty rates.

== How it works ==
Bitcoin API Services works by monitoring the Bitcoin network for transactions sent to addresses you can specify in your account. Bitcoin API Services can currently:

* POST amounts for variable price transactions.
* POST amounts for fixed price transactions.
* Make POSTs on Mt Gox currency and difficulty updates.

== Integration Details ==
* Merchant generates a number of Bitcoin addresses and enters them into his account. At the same time, merchant places these addresses into his store.
* The store software assigns one of these addresses to each order, or session. Once the user sends bitcoins to this address, the order is completed for the user.
* Meanwhile, the back-end of the merchants store waits for the confirmation from Bitcoin API Services. Once a confirmation is received the merchants store can either display the product to the user, or send the user an e-mail letting them know that the payment has been accepted. The address used can be released again for future use.

==History==
The service was proposed in mid-December as a redundancy to [[BitcoinNotify]]. The service officially went into beta on Wednesday, December 21st.

This service does not seem to be active as of 2026.

==Services==
* [https://blockmove.io/ Blockmove] Bitcoin wallet, merchant & API provider.
* [https://apirone.com/docs/ Apirone.com] RESTful API to accept, forward and transfer Bitcoins.
* [http://blockchain.info/api Blockchain.info] - has a developer API
* [https://coinbase.com/docs/api/overview Coinbase] Features an API that lets you send, request, buy, sell, and accept bitcoin through a RESTful JSON interface.

==See Also==
* [[:Category:ECommerce|eCommerce]]

==References==
<references />

[[Category:Shopping Cart Interfaces]]
[[Category:Services]]

BitcoinTalk

2026-01-01T07:31:42Z

NotATether: Remove duplicate reference

{{infobox company|name=Bitcoin Forum
|trading_name=BitcoinTalk
|industry=Forum
|founder=[[Satoshi Nakamoto]]
|owner=[[Martti Malmi]], [[User:Theymos|Theymos]]
|foundation=November 22, 2009
|members=3,741,835<ref name="bpip">[http://bpip.org/ Bitcointalk Public Information Project]</ref> (January 2026)
|ni_btc={{decrease}} -1,500
|ni_usd={{decrease}} -$430 thousand
|ni_year=2014
|equity_btc={{decrease}} 5,568
|equity_usd={{decrease}} $1.60 million
|equity_year=2014
|employees=
|website=[http://bitcointalk.org/ bitcointalk.org]
}}'''BitcoinTalk''' is a message board where people interested in the technical details and the development of Bitcoin software can talk to each other. The forum also has places for people who are interested in bitcoin [[:Category:Mining|mining]], in trading with bitcoin, and in the economics of Bitcoin.

The domain name is owned by [[Sirius]]. The forum is administrated by [[:User:Theymos|theymos]].

There are over 3.7 million registered accounts on Bitcointalk. However, nearly 3 million of these accounts are banned in one way or another, bringing the true user count down to around 700 thousand.<ref name="bpip"></ref>

==History==

Before the creation of the current BitcoinTalk Forum, Satoshi used a SourceForge forum, which is lost. When Sirius provided hosting, the forum was moved to bitcoin.org/smf. Satoshi made several custom modifications to the forum software and theme.

Satoshi's first non-test post on the forum was:

<blockquote>I left the admin account set to the original SMF theme so if I somehow completely wedge the custom theme I can still get in to fix it.

I've got a neat little 12x12 coin image to replace those pip stars with. Should look nice. Also some nice button images to try.

The registration page has "hide your e-mail address" unchecked by default. I must fix that in php before we can open up.

The Announcements forum is currently moderator access only.</blockquote>

The forum was at some point moved to forum.bitcoin.org. The bitcoin.org domain name was also transferred from Satoshi to Sirius.

In July, 2011 the forum was moved to bitcointalk.org in order to make it explicitly unofficial. The "forum" link on the bitcoin.org homepage was made to simply return the Google search results for the search terms "bitcoin forums". This was followed by Bitcoin Community members, very much in bitcoin's spirit of decentralisation, creating a number of alternative forums offering different moderatorial policies and using different software platforms. None of these alternative forums have yet reached the size of Bitcoin Talk.

Later, the "forum" link was simply removed, further distancing Bitcoin Talk from the official bitcoin.org. As of April 21, 2012, Bitcointalk remains the first search result on Google thanks to its high page rank.

On July 22, 2012, Bitcoin Talk reached its one millionth post.

Bitcointalk was hacked on May 22, 2015, and the attackers stole a database of usernames and passwords, which was then put for sale on the dark web. In response, administrators disabled the secret question feature, as it was seen as vulnerable to brute-force attacks. Attempting to use the secret question to recover the account will automatically lock the account.

==See Also==

* [[Bitcoin Wiki:Community portal]]

==External links==

* [http://bitcointalk.org/ Bitcoin Talk]

[[Category:Forums]]

==References==
<references/>

BitcoinTalk

2026-01-01T07:28:43Z

NotATether: update members count

{{infobox company|name=Bitcoin Forum
|trading_name=BitcoinTalk
|industry=Forum
|founder=[[Satoshi Nakamoto]]
|owner=[[Martti Malmi]], [[User:Theymos|Theymos]]
|foundation=November 22, 2009
|members=3,741,835<ref>[http://bpip.org/ Bitcointalk Public Information Project]</ref> (January 2026)
|ni_btc={{decrease}} -1,500
|ni_usd={{decrease}} -$430 thousand
|ni_year=2014
|equity_btc={{decrease}} 5,568
|equity_usd={{decrease}} $1.60 million
|equity_year=2014
|employees=
|website=[http://bitcointalk.org/ bitcointalk.org]
}}'''BitcoinTalk''' is a message board where people interested in the technical details and the development of Bitcoin software can talk to each other. The forum also has places for people who are interested in bitcoin [[:Category:Mining|mining]], in trading with bitcoin, and in the economics of Bitcoin.

The domain name is owned by [[Sirius]]. The forum is administrated by [[:User:Theymos|theymos]].

There are over 3.7 million registered accounts on Bitcointalk. However, nearly 3 million of these accounts are banned in one way or another, bringing the true user count down to around 700 thousand.<ref>[http://bpip.org/ Bitcointalk Public Information Project]</ref>

==History==

Before the creation of the current BitcoinTalk Forum, Satoshi used a SourceForge forum, which is lost. When Sirius provided hosting, the forum was moved to bitcoin.org/smf. Satoshi made several custom modifications to the forum software and theme.

Satoshi's first non-test post on the forum was:

<blockquote>I left the admin account set to the original SMF theme so if I somehow completely wedge the custom theme I can still get in to fix it.

I've got a neat little 12x12 coin image to replace those pip stars with. Should look nice. Also some nice button images to try.

The registration page has "hide your e-mail address" unchecked by default. I must fix that in php before we can open up.

The Announcements forum is currently moderator access only.</blockquote>

The forum was at some point moved to forum.bitcoin.org. The bitcoin.org domain name was also transferred from Satoshi to Sirius.

In July, 2011 the forum was moved to bitcointalk.org in order to make it explicitly unofficial. The "forum" link on the bitcoin.org homepage was made to simply return the Google search results for the search terms "bitcoin forums". This was followed by Bitcoin Community members, very much in bitcoin's spirit of decentralisation, creating a number of alternative forums offering different moderatorial policies and using different software platforms. None of these alternative forums have yet reached the size of Bitcoin Talk.

Later, the "forum" link was simply removed, further distancing Bitcoin Talk from the official bitcoin.org. As of April 21, 2012, Bitcointalk remains the first search result on Google thanks to its high page rank.

On July 22, 2012, Bitcoin Talk reached its one millionth post.

Bitcointalk was hacked on May 22, 2015, and the attackers stole a database of usernames and passwords, which was then put for sale on the dark web. In response, administrators disabled the secret question feature, as it was seen as vulnerable to brute-force attacks. Attempting to use the secret question to recover the account will automatically lock the account.

==See Also==

* [[Bitcoin Wiki:Community portal]]

==External links==

* [http://bitcointalk.org/ Bitcoin Talk]

[[Category:Forums]]

==References==
<references/>

BitcoinTalk

2026-01-01T07:25:07Z

NotATether: add info about the hack

{{infobox company|name=Bitcoin Forum
|trading_name=BitcoinTalk
|industry=Forum
|founder=[[Satoshi Nakamoto]]
|owner=[[Martti Malmi]], [[User:Theymos|Theymos]]
|foundation=November 22, 2009
|members=3544050<ref>[http://bpip.org/ Bitcointalk Public Information Project]</ref> (March 2023)
|ni_btc={{decrease}} -1,500
|ni_usd={{decrease}} -$430 thousand
|ni_year=2014
|equity_btc={{decrease}} 5,568
|equity_usd={{decrease}} $1.60 million
|equity_year=2014
|employees=
|website=[http://bitcointalk.org/ bitcointalk.org]
}}'''BitcoinTalk''' is a message board where people interested in the technical details and the development of Bitcoin software can talk to each other. The forum also has places for people who are interested in bitcoin [[:Category:Mining|mining]], in trading with bitcoin, and in the economics of Bitcoin.

The domain name is owned by [[Sirius]]. The forum is administrated by [[:User:Theymos|theymos]].

==History==

Before the creation of the current BitcoinTalk Forum, Satoshi used a SourceForge forum, which is lost. When Sirius provided hosting, the forum was moved to bitcoin.org/smf. Satoshi made several custom modifications to the forum software and theme.

Satoshi's first non-test post on the forum was:

<blockquote>I left the admin account set to the original SMF theme so if I somehow completely wedge the custom theme I can still get in to fix it.

I've got a neat little 12x12 coin image to replace those pip stars with. Should look nice. Also some nice button images to try.

The registration page has "hide your e-mail address" unchecked by default. I must fix that in php before we can open up.

The Announcements forum is currently moderator access only.</blockquote>

The forum was at some point moved to forum.bitcoin.org. The bitcoin.org domain name was also transferred from Satoshi to Sirius.

In July, 2011 the forum was moved to bitcointalk.org in order to make it explicitly unofficial. The "forum" link on the bitcoin.org homepage was made to simply return the Google search results for the search terms "bitcoin forums". This was followed by Bitcoin Community members, very much in bitcoin's spirit of decentralisation, creating a number of alternative forums offering different moderatorial policies and using different software platforms. None of these alternative forums have yet reached the size of Bitcoin Talk.

Later, the "forum" link was simply removed, further distancing Bitcoin Talk from the official bitcoin.org. As of April 21, 2012, Bitcointalk remains the first search result on Google thanks to its high page rank.

On July 22, 2012, Bitcoin Talk reached its one millionth post.

Bitcointalk was hacked on May 22, 2015, and the attackers stole a database of usernames and passwords, which was then put for sale on the dark web. In response, administrators disabled the secret question feature, as it was seen as vulnerable to brute-force attacks. Attempting to use the secret question to recover the account will automatically lock the account.

==See Also==

* [[Bitcoin Wiki:Community portal]]

==External links==

* [http://bitcointalk.org/ Bitcoin Talk]

[[Category:Forums]]

==References==
<references/>

Seed phrase

2025-12-27T08:54:55Z

NotATether: I woudn't say that LN and Blinded bearer certificates are still in infancy, so I reworded this paragraph

{{sample}}

A '''seed phrase''', '''seed recovery phrase''' or '''backup seed phrase''' is a list of words which [[Storing bitcoins|store]] all the information needed to recover Bitcoin funds [[Transaction|on-chain]]. Wallet software will typically generate a seed phrase and instruct the user to write it down on paper. If the user's computer breaks or their hard drive becomes corrupted, they can download the same wallet software again and use the paper backup to get their bitcoins back.

Anybody else who discovers the phrase can steal the bitcoins, so it must be kept safe like jewels or cash. For example, it must not be typed into any website.

Seed phrases are an excellent way of backing up and [[storing bitcoins]], so they are used by almost all well-regarded wallets.<ref>[https://bitcoin.org/en/choose-your-wallet Bitcoin.org: Choose your wallet]</ref>

Seed phrases can only back up funds on the [[block chain]]. They cannot store funds involved in [[off-chain transactions]] such as [[Lightning Network]] or [[Blinded bearer certificates]]. You need to back up additional data along with the seed phrase in order to re-create your wallet on those layers. Usually the wallet will do that automatically when you use its backup function.

== BIP39 and its flaws ==

[[BIP_0039|BIP39]] is the most common standard used for seed phrases. One notable example is [[Electrum|Electrum wallet]], which is using its own standard, and for good reasons. BIP39 has some flaws, known in the technical community but not known much wider. They are described [https://electrum.readthedocs.io/en/latest/seedphrase.html#motivation here on this electrum doc page]. Most seriously, BIP39 flaws mean it is not true to say that backing up a BIP39 seed phrase and name of wallet software is the only thing a user needs to do to keep their money safe. BIP39 works this way because its designers wanted their hardware wallet to also support [[altcoin]]s. [https://walletsrecovery.org/ walletsrecovery.org] is an attempt at helping with this issue, but ideally there will be a better solution in the future.

== Example ==

An example of a non-BIP39 seed phrase is:

hotel obvious agent lecture gadget evil jealous keen fragile before damp clarify

The word order is important.

[[File:Seed phrase.jpg|300px|thumb|none|alt=An example seed phrase written on paper|Example seed phrase on paper.]]

== Explanation ==

A simplified explanation of how seed phrases work is that the wallet software has a list of words taken from a dictionary, with each word assigned to a number. The seed phrase can be converted to a number which is used as the seed integer to a [[Deterministic wallet|deterministic wallet]] that generates all the [[Private key|key pairs]] used in the wallet.

The English-language wordlist for the BIP39 standard has 2048 words, so if the phrase contained only 12 random words, the number of possible combinations would be 2048^12 = 2^132 and the phrase would have 132 bits of security. However, some of the data in a BIP39 phrase is not random,<ref>[https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki#Generating_the_mnemonic BIP39: Generating the mnemonic]</ref> so the actual security of a 12-word BIP39 seed phrase is only 128 bits. This is approximately the same strength as all Bitcoin private keys, so most experts consider it to be sufficiently secure.<ref>[https://github.com/bitcoin/bips/blob/master/bip-0032.mediawiki#Security BIP32: Security]</ref>

It is not safe to invent your own seed phrase because humans are bad at generating randomness. The best way is to allow the wallet software to generate a phrase which you write down.

As seed phrases use natural language words, they have excellent error correction. Words written in bad handwriting can often still be read. If one or two letters are missing or unreadable the word can often still be deduced. The [[#Word_Lists|word list]] that the seed phrase words are drawn from is carefully chosen so that the first four letters of each word are enough to uniquely identify it. This compares well with writing down a raw [[private key]] where a single letter being unreadable or incorrect can make the private key useless (depending on the serialization format).

== Two-factor seed phrases ==

Seed phrases, like all backups, can store any amount of bitcoins. It's a concerning idea to possibly have enough money to purchase the entire building just sitting on a sheet of paper without any protection. For this reason many wallets make it possible to encrypt a seed phrase with a password.

The password can be used to create a two-factor seed phrase where both ''"something you have"'' plus ''"something you know"'' is required to unlock the bitcoins.

This works by the wallet creating a seed phrase and asking the user for a password. Then both the seed phrase and extra word are required to recover the wallet. Electrum and some other wallets call the passphrase a '''"seed extension"''', '''"extension word"''' or '''"13th/25th word"'''. The BIP39 standard defines a way of passphrase-protecting a seed phrase. A similar scheme is also used in the Electrum standard. If a passphrase is not present, an empty string "" is used instead.

'''Warning''': Forgetting this password will result in the bitcoin wallet and any contained money being lost. Do not overestimate your ability to remember passphrases especially when you may not use it very often.

'''Warning''': The seed phrase password should not be confused with the password used to encrypt the wallet file on disk. This is probably why many wallets call it an extension word instead of a password.

== Storing seed phrases for the long term ==

Most people write down phrases on paper but they can be stored in many other ways such as [[Brainwallet|memorizing]], engraving or stamping on metal, writing in the margins of a book, chiselling into a stone tablet or any other creative and inventive way.

In the past many people have accidentally lost bitcoins because of failed backups, mistyped letters, forgotten hard drives, or corrupted SSD devices. It's also important to protect the seed from accidental loss.

It could be a good idea to write some words of explanation on the same paper as the seed phrase. If storing for the long term you may forget what a phrase is how it should be treated. A sample explanation that can be adapted is:

<blockquote>These twelve words have control over BITCOINS. Keep this paper safe and secret like cash or jewellery. The bitcoin information on this paper is encrypted with a passphrase. It is part of a multi-signature wallet and was made by Electrum bitcoin wallet software on 2019-01-01.</blockquote>

==== Paper and pencil backup ====

Through bitter experience it has been found that one of the most practical storage media is '''pencil and paper'''. The private keys of a bitcoin wallet are encoded into [[seed phrase|random words from a dictionary]] which can be written down. If your hard drive crashes, you can find the paper with the [[seed phrase]] and restore the entire wallet. As [[seed phrase]]s use natural language words, they have good error correction. Words written in bad handwriting can often still be read. If one or two letters are missing the word can often still be deduced. The [[Seed_phrase#Word_Lists|word list]] that the seed phrase words are drawn from is carefully chosen so that the first four letters of each word are enough to uniquely identify it.

For storing on paper writing with pencil is much better than pen.<ref>[http://www.joethorn.net/blog/2011/12/07/pencil-does-not-fade Pencil Does Not Fade]
</ref><ref>[https://www.quora.com/How-do-I-maintain-a-paper-notebook-that-can-remain-for-years How do I maintain a paper notebook that can remain for years?]
</ref>
Paper should be acid-free or archival paper, and stored in the dark avoiding extremes of heat and moisture.<ref>[https://www.loc.gov/preservation/care/deterioratebrochure.html Essential facts about preservation of Paper]
</ref><ref>[https://www.quora.com/If-I-write-with-a-pencil-on-my-notebook-will-the-writing-last-for-a-long-time-say-50-years-or-will-it-just-fade-away-gradually Writing in a notebook with pencil]
</ref><ref>[http://copar.org/bulletin14.htm CoPAR: Creating records that will last]</ref>

==== Metal backup ====

Seed phrases can also be [https://blog.lopp.net/metal-bitcoin-seed-storage-stress-test--part-ii-/ stamped or engraved into metal] which is significantly more durable than paper. Metal backups are recommended if the threat model involves fire, water, extremes of temperature or physical stress.

==== Methods that are not recommended ====

Some methods that are not recommended are: storing in a file on a computer (including online), or storing online.

Some people get the idea to split up their phrases, like storing 6 words in one location and the other 6 words in another location. This is a bad idea and should not be done, because if one set of 6 words is discovered then it becomes far easier to brute-force the rest of the phrase. Storing bitcoins in multiple locations like this should be done with [[multi-signature]] wallets instead.

The [[Shamir Secret Sharing]] algorithm is sometimes promoted as a way to divide control of bitcoins, but in practice there are many pitfalls and trade-offs that make it not worth it.<ref>[https://blog.keys.casa/shamirs-secret-sharing-security-shortcomings/ Shamir's Secret Sharing Shortcomings] by Jameson Lopp, Casa blog, 2020</ref> 

Another bad idea is to add random decoy words that are somehow meaningful to you and later remove them to be left with only the 12-word phrase. The phrase words come from a known dictionary (see next section), so anybody can use that dictionary to weed out the decoy words.

It's possible but risky to memorize ([[Brainwallet]]s) seed phrases. This should probably only be done in situations that really need it, such as crossing a hostile border where one expects to be searched.

== Word lists ==

Generally, a seed phrase only works with the same wallet software that created it. If storing for a long period of time it's a good idea to write the name of the wallet too.

The [https://cryptorecovers.com/blog/bip39-word-list/ BIP39 English word list] has each word being uniquely identified by the first four letters, which can be useful when space to write them is scarce.

* [https://github.com/bitcoin/bips/blob/master/bip-0039/bip-0039-wordlists.md BIP39 wordlists]
* [https://github.com/spesmilo/electrum/blob/1.9.8/lib/mnemonic.py Electrum old-style wordlist]
* [https://github.com/spesmilo/electrum/blob/master/electrum/wordlist/english.txt Electrum new-style wordlist]
* [https://bip39-phrase.com/transkriptsionnyi-slovar-bip39-po-ipa-znakam/ BIP39 transcription Dictionary by IPA characters]

== Alternative name "mnemonic phrase" ==

Seed phrases are sometimes called ''mnemonic phrases'', especially in older literature. This is a bad name because the word "mnemonic" implies that the phrase should be memorized. It is less misleading to call them seed phrases.

== The power of backups ==

An especially interesting aspect in the power of paper backups is allowing your money to be two places at once. At the London Inside Bitcoin conference, the keynote speaker showed 25 paper backups they were carrying—all password-protected. With that, one can carry $100,000 which can instantly be moved to a phone or transferred yet with total security. If it's stolen, then there is no risk because it is backed up elsewhere. That is powerful.<ref>https://www.reddit.com/r/Bitcoin/comments/2hmnru/poll_do_you_use_paper_wallets_why_why_not_what/</ref>

== See also ==

* [https://github.com/bitcoin/bips/blob/master/bip-0039.mediawiki BIP39 seed phrase standard]
* [[Deterministic wallet]]
* [[Storing bitcoins]]
* [[Brainwallet]]
* [https://github.com/6102bitcoin/6102bitcoin/blob/main/content/faq-bitcoin-seed.md FAQ regarding bitcoin seeds]
* [https://web.archive.org/web/20210214135049/https://www.hodlalert.com/2020/12/21/generating-cryptographically-secure-random-numbers-with-coins-and-a-cup/ Generating Bitcoin Seed Phrases With Coins and A Cup]

==References==
<references />

[[Category:Technical]]

People

2025-12-27T08:51:56Z

NotATether: add caveat

A short list of active and former contributors to Bitcoin, ordered by first name. This list is not exhaustive.

[[Andreas Schildbach]] ([https://profiles.google.com/andreas.schildbach Profile]) - original developer of [https://market.android.com/details?id=de.schildbach.wallet Bitcoin Wallet for Android] ([http://code.google.com/p/bitcoin-wallet/ Google Code Project]).

[[Amir Taaki]] ([http://en.wikipedia.org/wiki/Amir_Taaki Wikipedia]) aka genjix- creator of the [[BIP]] process, [[Libbitcoin]] C++ developer toolkit, [[Libbitcoin_Server|Obelisk]] blockchain server (later BS), [[Libbitcoin_Explorer|SX]] bitcoin command line tool (later BX), [https://bitcoinmagazine.com/7892/shedding-light-on-the-dark-wallet Darkwallet], [http://www.wired.com/2014/04/darkmarket Darkmarket] (later [https://openbazaar.org OpenBazaar]), [http://reason.com/blog/2015/02/24/darkleaks-the-decentralized-information Darkleaks], [[Freecoin]] and well as inactive/defunct projects such as the [[Britcoin]] exchange, [[Intersango]] exchange, [[Spesmilo]] RPC client, [[Bitcoin Consultancy]], Bitcoin Media Blog (author), [[Vibanko]] web wallet provider, [[GLBSE]] exchange client, [https://github.com/genjix/kartludox Kartludox] Bitcoin poker client, [[Pastecoin]] and Python bindings for Bitcoin.

[[ArtForz|Art Forz]]- developed the first fully-deployed and actively-used GPU miner (Lazslo's was theoretically the first but it's not clear he solved any blocks with it) and at one time his GPU mining farm (the ArtFarm) was mining over a third of all blocks.

[[Gary Rowe]] ([https://plus.google.com/u/0/115295932487523951663/about Profile ]) - Contributor to the [[MultiBit]] (http://multibit.org) and [[BitCoinJ]] (http://code.google.com/p/bitcoinj/) projects. Working on various Bitcoin based businesses.

[[User:Gavinandresen|Gavin Andresen]] - ([https://profiles.google.com/u/0/gavinandresen/about Profile ]) Former [[Satoshi client]] maintainer. He previously worked at Silicon Graphics and now runs his own company.

[[Hal Finney]]- one of the creators of [http://en.wikipedia.org/wiki/Pretty_Good_Privacy PGP] and one of the earliest contributors to the Bitcoin project. First to identify a type of double-spending attack that now bears his name -- the [[Double-spending#Finney_attack|Finney attack]].

James McCarthy aka Nefario- creator of the first bitcoin stock exchange [[GLBSE]]

[[Jed McCaleb]], cofounder of Stellar.org and original developer of [[MtGox]]. Previously created [https://en.wikipedia.org/wiki/EDonkey2000 eDonkey2000].

[[Jeff Garzik]]- [[Satoshi client]] core developer, GPU poold software and the founder of [[Bitcoin Watch]]. Works for BitPay.

[[Luke Dashjr]] aka Luke-Jr- [[Eligius]] founder, maintains [[BFGMiner]] and maintainer of [[bitcoind]]/[[Bitcoin-Qt]] stable branches.

[[Mark Karpeles]] ([https://en.wikipedia.org/wiki/Mark_Karpeles Wikipedia]) aka MagicalTux- Former owner of [[MtGox]] and this wiki.

[[Sirius|Martti Malmi]] aka Sirius- Former Bitcoin developer. Operates the domain names bitcoin.org and bitcointalk.org.

[[Matt Corallo]] aka BlueMatt- [[Satoshi client]] and [[Bitcoinj]] developer.

[[Michael Hendrix]] aka mndrix- creator of the now defunct CoinPal and CoinCard services

[[Mike Hearn]] ([https://profiles.google.com/mh.in.england/about Profile]) Google engineer who works on Gmail and developed [[BitCoinJ]] (http://code.google.com/p/bitcoinj/) and [[Lighthouse]].

[[User:Tcatm|Nils Schneider]] aka tcatm - Bitcoin developer, owner of BitcoinWatch, creator and owner of BitcoinCharts, GPU mining software and JS web interface.

[[Patrick McFarland]] aka Diablo-D3 - DiabloMiner author, and former BitcoinTalk forum moderator.

[[Patrick Strateman]] aka phantomcircuit - Bitcoin developer, creator of [[Intersango]], member of [[Bitcoin Consultancy]] and creator of Python Bitcoin implementation.

[[Peter Todd]] - Bitcoin developer. Involved with Bitcoin related startup [[Coinkite]] and [[DarkWallet]].

[[Pieter Wuille]] aka sipa- [[Satoshi client]] developer and maintainer of the network graphs http://bitcoin.sipa.be

[[Stefan Thomas]] aka justmoon- creator of the ([https://www.weusecoins.com We Use Coins]) site/video and WebCoin.

[[Tamas Blummer]] aka grau - author of Bits of Proof, the enterprise-ready implementation of the Bitcoin protocol. http://bitsofproof.com

[[Trace Mayer]] - Host of the ([http://www.bitcoin.kn Bitcoin Knowledge Podcast]) where the top people in Bitcoin are interviewed

[[Vladimir Marchenko]]- ([https://profiles.google.com/u/0/vmartchenko/about?hl=en Profile]), runs [[Marchenko Ltd]] which sells mining contracts, previously developed the figator.org search engine.

[[Wladimir van der Laan]] - [[Satoshi client]] maintainer.

==See Also==
* [[Original client developers]]
* [[Developers]]
* [[:Template:Developers]]
* Wiki list of [[:Special:ListUsers|users]]
* [[Project:Community_portal|Community portal]]
* [[:Category:People]]

People

2025-12-27T08:51:10Z

NotATether: It's easier to just write former than to sift through the list

A short list of active and former contributors to Bitcoin, ordered by first name.

[[Andreas Schildbach]] ([https://profiles.google.com/andreas.schildbach Profile]) - original developer of [https://market.android.com/details?id=de.schildbach.wallet Bitcoin Wallet for Android] ([http://code.google.com/p/bitcoin-wallet/ Google Code Project]).

[[Amir Taaki]] ([http://en.wikipedia.org/wiki/Amir_Taaki Wikipedia]) aka genjix- creator of the [[BIP]] process, [[Libbitcoin]] C++ developer toolkit, [[Libbitcoin_Server|Obelisk]] blockchain server (later BS), [[Libbitcoin_Explorer|SX]] bitcoin command line tool (later BX), [https://bitcoinmagazine.com/7892/shedding-light-on-the-dark-wallet Darkwallet], [http://www.wired.com/2014/04/darkmarket Darkmarket] (later [https://openbazaar.org OpenBazaar]), [http://reason.com/blog/2015/02/24/darkleaks-the-decentralized-information Darkleaks], [[Freecoin]] and well as inactive/defunct projects such as the [[Britcoin]] exchange, [[Intersango]] exchange, [[Spesmilo]] RPC client, [[Bitcoin Consultancy]], Bitcoin Media Blog (author), [[Vibanko]] web wallet provider, [[GLBSE]] exchange client, [https://github.com/genjix/kartludox Kartludox] Bitcoin poker client, [[Pastecoin]] and Python bindings for Bitcoin.

[[ArtForz|Art Forz]]- developed the first fully-deployed and actively-used GPU miner (Lazslo's was theoretically the first but it's not clear he solved any blocks with it) and at one time his GPU mining farm (the ArtFarm) was mining over a third of all blocks.

[[Gary Rowe]] ([https://plus.google.com/u/0/115295932487523951663/about Profile ]) - Contributor to the [[MultiBit]] (http://multibit.org) and [[BitCoinJ]] (http://code.google.com/p/bitcoinj/) projects. Working on various Bitcoin based businesses.

[[User:Gavinandresen|Gavin Andresen]] - ([https://profiles.google.com/u/0/gavinandresen/about Profile ]) Former [[Satoshi client]] maintainer. He previously worked at Silicon Graphics and now runs his own company.

[[Hal Finney]]- one of the creators of [http://en.wikipedia.org/wiki/Pretty_Good_Privacy PGP] and one of the earliest contributors to the Bitcoin project. First to identify a type of double-spending attack that now bears his name -- the [[Double-spending#Finney_attack|Finney attack]].

James McCarthy aka Nefario- creator of the first bitcoin stock exchange [[GLBSE]]

[[Jed McCaleb]], cofounder of Stellar.org and original developer of [[MtGox]]. Previously created [https://en.wikipedia.org/wiki/EDonkey2000 eDonkey2000].

[[Jeff Garzik]]- [[Satoshi client]] core developer, GPU poold software and the founder of [[Bitcoin Watch]]. Works for BitPay.

[[Luke Dashjr]] aka Luke-Jr- [[Eligius]] founder, maintains [[BFGMiner]] and maintainer of [[bitcoind]]/[[Bitcoin-Qt]] stable branches.

[[Mark Karpeles]] ([https://en.wikipedia.org/wiki/Mark_Karpeles Wikipedia]) aka MagicalTux- Former owner of [[MtGox]] and this wiki.

[[Sirius|Martti Malmi]] aka Sirius- Former Bitcoin developer. Operates the domain names bitcoin.org and bitcointalk.org.

[[Matt Corallo]] aka BlueMatt- [[Satoshi client]] and [[Bitcoinj]] developer.

[[Michael Hendrix]] aka mndrix- creator of the now defunct CoinPal and CoinCard services

[[Mike Hearn]] ([https://profiles.google.com/mh.in.england/about Profile]) Google engineer who works on Gmail and developed [[BitCoinJ]] (http://code.google.com/p/bitcoinj/) and [[Lighthouse]].

[[User:Tcatm|Nils Schneider]] aka tcatm - Bitcoin developer, owner of BitcoinWatch, creator and owner of BitcoinCharts, GPU mining software and JS web interface.

[[Patrick McFarland]] aka Diablo-D3 - DiabloMiner author, and former BitcoinTalk forum moderator.

[[Patrick Strateman]] aka phantomcircuit - Bitcoin developer, creator of [[Intersango]], member of [[Bitcoin Consultancy]] and creator of Python Bitcoin implementation.

[[Peter Todd]] - Bitcoin developer. Involved with Bitcoin related startup [[Coinkite]] and [[DarkWallet]].

[[Pieter Wuille]] aka sipa- [[Satoshi client]] developer and maintainer of the network graphs http://bitcoin.sipa.be

[[Stefan Thomas]] aka justmoon- creator of the ([https://www.weusecoins.com We Use Coins]) site/video and WebCoin.

[[Tamas Blummer]] aka grau - author of Bits of Proof, the enterprise-ready implementation of the Bitcoin protocol. http://bitsofproof.com

[[Trace Mayer]] - Host of the ([http://www.bitcoin.kn Bitcoin Knowledge Podcast]) where the top people in Bitcoin are interviewed

[[Vladimir Marchenko]]- ([https://profiles.google.com/u/0/vmartchenko/about?hl=en Profile]), runs [[Marchenko Ltd]] which sells mining contracts, previously developed the figator.org search engine.

[[Wladimir van der Laan]] - [[Satoshi client]] maintainer.

==See Also==
* [[Original client developers]]
* [[Developers]]
* [[:Template:Developers]]
* Wiki list of [[:Special:ListUsers|users]]
* [[Project:Community_portal|Community portal]]
* [[:Category:People]]

Statistics

2025-12-20T06:59:28Z

NotATether: no need for caps

There are many places with good statistics about Bitcoin. For network stats, the best place to start is with your own [[full node]]. Following that, detailed information about addresses, mining, transaction volume, and adoption can be found on various sites tracking those metrics. Below is a summary of Bitcoin statistics as of December 2025.

== Supply & on-chain fundamentals ==

* '''Circulating supply''': ~19.96M BTC (95% of the 21M supply)
* '''Bitcoins left to mine''': ~1.04M BTC
* '''Estimated lost/ancient coins''': Reports suggest several million BTC (ancient supply accumulating over time, indicating a portion is likely inaccessible or lost)<ref>https://www.fidelitydigitalassets.com/research-and-insights/increasing-impact-bitcoins-ancient-supply</ref>
* '''Transaction volume''': Over 1.2 billion cumulative transactions<ref>https://www.blockchain.com/explorer/charts/n-transactions-total</ref>
* '''Addresses''': Over 100 million addresses<ref>https://bitcoinisdata.com/qtd_addr/</ref>, with roughly ~250 thousand new addresses per day<ref>https://bitcoinisdata.com/new_addr/</ref>

== Network health ==

* '''Reachable full nodes''': ~24,000+ reachable Bitcoin nodes<ref>https://bitnodes.io/</ref>
* '''SegWit adoption''': Around 90-95% of network transactions<ref>https://mainnet.observer/charts/transactions-spending-segwit/</ref>
* '''Taproot adoption''': Roughly ~15–20% of the network total, down from a 2024 peak above 40% that was driven largely by inscriptions (e.g., Ordinals)<ref>https://mainnet.observer/charts/transactions-spending-taproot/</ref>

== Mining ==

* '''Hash rate''': Over 1.07 zettahash/s global hash power<ref>https://bitinfocharts.com/comparison/bitcoin-hashrate.html#3y</ref>
* '''Fee subsidy''': Roughly ~99.3% of miner revenue comes from block rewards<ref>https://timechainstats.com/</ref>

== Broader adoption metrics ==

* '''Global cryptocurrency adoption''': Over 900,000 active Bitcoin users per day <ref>https://www.coingecko.com/research/publications/bitcoin-report-2025</ref>
* '''Spot Bitcoin ETF holdings''': Over ~1.29 BTC accumulated (~6% of total supply) since their launch in 2024
* '''Public company holdings''': Over 1M BTC held by publicly listed companies aggregated across firms (corporate treasuries accumulating BTC)
* '''Bitcoin legality''': Unrestricted in 132 out of 257 countries<ref>https://coin.dance/poli</ref>

== Websites with statistics ==

Here are some notable websites that can give you a quick overview of relevant statistics.

* [https://bitcoin.clarkmoody.com/dashboard/ Clark Moody Bitcoin Dashboard]
* [https://mainnet.observer/ mainnet-observer]
* [https://bitinfocharts.com/ BitInfoCharts]
* [https://timechainstats.com/ TimechainStats]
* [https://coin.dance/ Coin Dance]

== References ==

Statistics

2025-12-20T06:58:37Z

NotATether: Enhance the statistics page

There are many places with good statistics about Bitcoin. For network stats, the best place to start is with your own [[full node]]. Following that, detailed information about addresses, mining, transaction volume, and adoption can be found on various sites tracking those metrics. Below is a summary of Bitcoin statistics as of December 2025.

== Supply & On-Chain Fundamentals ==

* '''Circulating supply''': ~19.96M BTC (95% of the 21M supply)
* '''Bitcoins left to mine''': ~1.04M BTC
* '''Estimated lost/ancient coins''': Reports suggest several million BTC (ancient supply accumulating over time, indicating a portion is likely inaccessible or lost)<ref>https://www.fidelitydigitalassets.com/research-and-insights/increasing-impact-bitcoins-ancient-supply</ref>
* '''Transaction volume''': Over 1.2 billion cumulative transactions<ref>https://www.blockchain.com/explorer/charts/n-transactions-total</ref>
* '''Addresses''': Over 100 million addresses<ref>https://bitcoinisdata.com/qtd_addr/</ref>, with roughly ~250 thousand new addresses per day<ref>https://bitcoinisdata.com/new_addr/</ref>

== Network Health ==

* '''Reachable full nodes''': ~24,000+ reachable Bitcoin nodes<ref>https://bitnodes.io/</ref>
* '''SegWit adoption''': Around 90-95% of network transactions<ref>https://mainnet.observer/charts/transactions-spending-segwit/</ref>
* '''Taproot adoption''': Roughly ~15–20% of the network total, down from a 2024 peak above 40% that was driven largely by inscriptions (e.g., Ordinals)<ref>https://mainnet.observer/charts/transactions-spending-taproot/</ref>

== Mining ==

* '''Hash rate''': Over 1.07 zettahash/s global hash power<ref>https://bitinfocharts.com/comparison/bitcoin-hashrate.html#3y</ref>
* '''Fee subsidy''': Roughly ~99.3% of miner revenue comes from block rewards<ref>https://timechainstats.com/</ref>

== Broader Adoption Metrics ==

* '''Global cryptocurrency adoption''': Over 900,000 active Bitcoin users per day <ref>https://www.coingecko.com/research/publications/bitcoin-report-2025</ref>
* '''Spot Bitcoin ETF holdings''': Over ~1.29 BTC accumulated (~6% of total supply) since their launch in 2024
* '''Public company holdings''': Over 1M BTC held by publicly listed companies aggregated across firms (corporate treasuries accumulating BTC)
* '''Bitcoin legality''': Unrestricted in 132 out of 257 countries<ref>https://coin.dance/poli</ref>

== Websites with statistics ==

Here are some notable websites that can give you a quick overview of relevant statistics.

* [https://bitcoin.clarkmoody.com/dashboard/ Clark Moody Bitcoin Dashboard]
* [https://mainnet.observer/ mainnet-observer]
* [https://bitinfocharts.com/ BitInfoCharts]
* [https://timechainstats.com/ TimechainStats]
* [https://coin.dance/ Coin Dance]

== References ==

Tutorial: Automatically mine when computer is locked on Windows

2025-12-20T05:02:06Z

NotATether: Add OS and hardware compatibility details

'''''Note:''' This tutorial is created with Windows 7 in mind. The exact steps are likely different for other versions of Windows, but are expected to work in newer versions (8/10/11) as well. In addition, any text surrounded by quotes is to be entered without quotes.''

This guide was originally written with GPU mining and cgminer in mind, but these steps also work for bfgminer and ASICs with minimal changes.

If you want to mine Bitcoins, but also need to use your computer for other GPU-intensive tasks like gaming, it can be annoying to start mining each time you stop using your computer. On Microsoft Windows, there is a little-known way to automate tasks like this. For this tutorial, we will be using [[CGMiner]]. If you don't already have it, [https://bitcointalk.org/index.php?topic=28402.0 download it from here], and extract it to a folder somewhere on your hard drive.

==Configuring the security auditing settings==
[[File:Windows Audit Configuration.png|thumb|right|250px|Configuring Windows to log when the computer is locked and unlocked.]]

Windows keeps a log of various types of events that occur on your computer. These events include software crashes and system service notifications, among other things. This event log is closely tied to another feature of Windows known as security auditing. Basically, every time certain tasks are performed that require user authentication, such as logging on to your computer, it creates a log entry. This feature is designed mainly for professionals who need to monitor corporate networks, but it can be useful for this purpose too. How? It is possible to program Windows to run programs whenever specific types of events occur.

Locking and unlocking your computer are two things that Windows can log, but by default it is not configured to do so. To enable this:

# Open the Run dialog (Windows+R) and type "secpol.msc".
# On the left, expand "Advanced Audit Policy Configuration", "System Audit Policies - Local Group Policy Object", and select "Logon/Logoff".
# On the right, double-click "Audit Other Logon/Logoff Events".
# In the dialog that appears, make sure "Configure the following audit events" and "Success" are checked.
# Click OK, and close the Local Security Policy window.

==Using the Task Scheduler==

Next, we need to tell Windows to respond to these events. There are two tasks we need to program: one to start mining when the computer is locked, and one to stop mining when the computer is unlocked.

===Start mining when the computer is locked===

# Open the Run dialog (Windows+R) and type "taskschd.msc".
# On the very right, select "Create Basic Task..." from the menu.
# Give it a name, such as "Start Bitcoin Mining". What exactly you type here doesn't matter, as long as you remember what it is in case you need to change something later. Click Next.
# Select "When a specific event is logged" from the list, and click Next.
# For "Log", select "Security". For "Source", select "Microsoft Windows security auditing." For "Event ID", type 4800. Click Next.
# Select "Start a program" from the list, and click Next.
# For "Program/script", click "Browse..." and select cgminer.exe. (You do remember where you extracted it, right?)
# For "Add arguments (optional)", type in the command line parameters. Make sure to add <code>--api-listen --api-allow W:127.0.0.1</code> to the end.
#:If you're unfamiliar with cgminer, you can use the following template: <code>-o ''[pool server]'' -u ''[user/worker name]'' -p ''[password]'' --api-listen --api-allow W:127.0.0.1</code>
# Click Next, and then Finish.

===Stop mining when the computer is unlocked===

To stop cgminer when the computer is unlocked is trickier than it might seem. On my computer (and likely others as well) simply killing the process causes the video driver to temporarily stop responding. This can cause other applications to crash, and it's also just annoying as you need to wait 10 seconds or more to use your computer. For obvious reasons, it would be VERY annoying to have this happen every time you unlock your computer. (Even if this exact problem doesn't occur, cgminer may need to "clean up" when it's done, so it's best to use this method anyway.)

Luckily, cgminer provides an API to allow other applications to control it. All we need to do is send the command "quit" to the local computer on network port 4028. For this, we'll use a program called [http://joncraton.org/blog/46/netcat-for-windows netcat]. Download this, and extract "nc.exe" to your cgminer directory.

Now we need to create two new files in this directory. Open Notepad, and type the word "quit". Do '''NOT''' press Enter afterwards. For some strange reason, cgminer doesn't accept commands ending in a newline character. This is why we need to create a file in the first place, rather than simply using the <code>echo</code> command. Save the file to your cgminer directory as "quit.txt".

Click File→New, and type the following:

<pre>
@echo off
nc localhost 4028 < quit.txt
</pre>

Save the file in the same directory as "quit.bat".

Now we need to schedule a new task. Do this the same way as you did before, with a few differences:

* Type a different name (should be obvious)
* Instead of 4800, enter 4801 for the event ID.
* For "Program/script", select the "quit.bat" you just created instead of "cgminer.exe".
* Leave "Add arguments (optional)" blank, and select the cgminer directory for "Start in (optional)".

==You're done!==

Lock your computer (Windows+L), wait 15 seconds or so, and unlock it. While it's locked, you should hear your GPU fan start spinning. When you unlock your computer, you should see cgminer appear for a second, then exit.

If it didn't work properly, leave a comment on [[Talk:{{PAGENAME}}|this article's talk page]], or send an email to [mailto:flarn2006@gmail.com flarn2006@gmail.com]. If it did, great!

Tutorial: Automatically mine when computer is locked on Windows

2025-12-20T05:01:13Z

NotATether: The localhost ip address appears to be blacklisted by cloudflare

'''''Note:''' This tutorial is created with Windows 7 in mind. The exact steps are likely different for other versions of Windows. In addition, any text surrounded by quotes is to be entered without quotes.''

If you want to mine Bitcoins, but also need to use your computer for other GPU-intensive tasks like gaming, it can be annoying to start mining each time you stop using your computer. On Microsoft Windows, there is a little-known way to automate tasks like this. For this tutorial, we will be using [[CGMiner]]. If you don't already have it, [https://bitcointalk.org/index.php?topic=28402.0 download it from here], and extract it to a folder somewhere on your hard drive.

==Configuring the security auditing settings==
[[File:Windows Audit Configuration.png|thumb|right|250px|Configuring Windows to log when the computer is locked and unlocked.]]

Windows keeps a log of various types of events that occur on your computer. These events include software crashes and system service notifications, among other things. This event log is closely tied to another feature of Windows known as security auditing. Basically, every time certain tasks are performed that require user authentication, such as logging on to your computer, it creates a log entry. This feature is designed mainly for professionals who need to monitor corporate networks, but it can be useful for this purpose too. How? It is possible to program Windows to run programs whenever specific types of events occur.

Locking and unlocking your computer are two things that Windows can log, but by default it is not configured to do so. To enable this:

# Open the Run dialog (Windows+R) and type "secpol.msc".
# On the left, expand "Advanced Audit Policy Configuration", "System Audit Policies - Local Group Policy Object", and select "Logon/Logoff".
# On the right, double-click "Audit Other Logon/Logoff Events".
# In the dialog that appears, make sure "Configure the following audit events" and "Success" are checked.
# Click OK, and close the Local Security Policy window.

==Using the Task Scheduler==

Next, we need to tell Windows to respond to these events. There are two tasks we need to program: one to start mining when the computer is locked, and one to stop mining when the computer is unlocked.

===Start mining when the computer is locked===

# Open the Run dialog (Windows+R) and type "taskschd.msc".
# On the very right, select "Create Basic Task..." from the menu.
# Give it a name, such as "Start Bitcoin Mining". What exactly you type here doesn't matter, as long as you remember what it is in case you need to change something later. Click Next.
# Select "When a specific event is logged" from the list, and click Next.
# For "Log", select "Security". For "Source", select "Microsoft Windows security auditing." For "Event ID", type 4800. Click Next.
# Select "Start a program" from the list, and click Next.
# For "Program/script", click "Browse..." and select cgminer.exe. (You do remember where you extracted it, right?)
# For "Add arguments (optional)", type in the command line parameters. Make sure to add <code>--api-listen --api-allow W:127.0.0.1</code> to the end.
#:If you're unfamiliar with cgminer, you can use the following template: <code>-o ''[pool server]'' -u ''[user/worker name]'' -p ''[password]'' --api-listen --api-allow W:127.0.0.1</code>
# Click Next, and then Finish.

===Stop mining when the computer is unlocked===

To stop cgminer when the computer is unlocked is trickier than it might seem. On my computer (and likely others as well) simply killing the process causes the video driver to temporarily stop responding. This can cause other applications to crash, and it's also just annoying as you need to wait 10 seconds or more to use your computer. For obvious reasons, it would be VERY annoying to have this happen every time you unlock your computer. (Even if this exact problem doesn't occur, cgminer may need to "clean up" when it's done, so it's best to use this method anyway.)

Luckily, cgminer provides an API to allow other applications to control it. All we need to do is send the command "quit" to the local computer on network port 4028. For this, we'll use a program called [http://joncraton.org/blog/46/netcat-for-windows netcat]. Download this, and extract "nc.exe" to your cgminer directory.

Now we need to create two new files in this directory. Open Notepad, and type the word "quit". Do '''NOT''' press Enter afterwards. For some strange reason, cgminer doesn't accept commands ending in a newline character. This is why we need to create a file in the first place, rather than simply using the <code>echo</code> command. Save the file to your cgminer directory as "quit.txt".

Click File→New, and type the following:

<pre>
@echo off
nc localhost 4028 < quit.txt
</pre>

Save the file in the same directory as "quit.bat".

Now we need to schedule a new task. Do this the same way as you did before, with a few differences:

* Type a different name (should be obvious)
* Instead of 4800, enter 4801 for the event ID.
* For "Program/script", select the "quit.bat" you just created instead of "cgminer.exe".
* Leave "Add arguments (optional)" blank, and select the cgminer directory for "Start in (optional)".

==You're done!==

Lock your computer (Windows+L), wait 15 seconds or so, and unlock it. While it's locked, you should hear your GPU fan start spinning. When you unlock your computer, you should see cgminer appear for a second, then exit.

If it didn't work properly, leave a comment on [[Talk:{{PAGENAME}}|this article's talk page]], or send an email to [mailto:flarn2006@gmail.com flarn2006@gmail.com]. If it did, great!

App store optimization

2025-12-20T04:46:50Z

NotATether: Mark for deletion notice

{{PfD|dead redirect}}

'''App Store Optimization, also known as [https://en.bitcoin.it/wiki/Aso ASO]'''.

[[Category:Android]]
[[Category:ASO]]
[[Category:App Store Optimization]]
[[Category:iOS]]
[[Category:Mobile]]
[[Category:Services]]

99bitcoins

2025-12-20T04:43:45Z

NotATether: Remove non-existing android app

[http://99bitcoins.com 99 Bitcoins] is a website and blog about Bitcoins. The website aims to close the gap between newbies and the technological aspect of Bitcoin through the use of a non technical blog and simple tutorials explained in laymen terms. 99 Bitcoins also operates the subdomain [http://affiliates.99bitcoins.com 99 Affiliates] which aims to be the most comprehensive source on the web for [[Bitcoin Affiliate Programs]].

==History==

99 Bitcoins originally started out as BitcoinWithPaypal.com and focused on the sole purpose of explaining how to buy Bitcoins with Paypal. After receiving a complaint from Paypal's legal department regarding the use of their trademark in the domain name the website rebranded itself to 99 Bitcoins. In 2014 the website has expanded and offers tutorials not only about Bitcoin but also about other crypto currencies such as Litecoin, Peercoin, Namecoin, Feathercoin and more.

==Software==

99 Bitcoins has issued out various plugins and apps for the Bitcoin community.

===99 Coins Ticker===
The 99 Coins Ticker is a Wordpress plugin that allows website owners to display the latest Bitcoin prices from 4 different exchanges on their Wordpress website - BTC-E, BitStamp, BTC China and BTC Average. The plugin also has a graphical display of historical Bitcoin prices up to 30 days back.

===Bitcoin News Feed Widget===
The Bitcoin News Feed Widget is a Wordpress plugin that allows website owners to display the latest Bitcoin news stories on their website from various news sources. All stories are picked out manually.

===99 Bitcoins mobile app===
The 99 Bitcoins mobile app is an Android app that displays the latest Bitcoin prices and news stories. The app is free of charge and also shows a graphical display of historical Bitcoin prices up to 30 days back.

==99 Affiliates==

99 Affiliates is a subdomain of 99 Bitcoins dedicated solely to covering the subject of Bitcoin affiliate programs. The website is built as a blog which gives real live data from different Bitcoin affiliate programs after it has tested them out for conversion rates and payouts. Some of 99 Affiliates' content is restricted to registered users. Registration is free of charge.

==External Links==

* [http://wordpress.org/plugins/bitcoin-ticker-widget/ Coin Ticker WP Plugin]
* [http://wordpress.org/plugins/bitcoin-news-ticker-widget/ Bitcoin News Feed Widget]

==References==
<references />

[[Category:Blogs]]
[[Category:Educational]]

Storing bitcoins

2025-12-19T14:16:21Z

NotATether: add details

''This page is a discussion of the different ways of storing bitcoins, whether for [[Bitcoin as an investment|investment purposes]] or as a [[Bitcoin as a medium of exchange|medium of exchange]].''

As bitcoin is a digital asset, it can be very un-intuitive to store safely. Historically many people have lost their coins but with proper understanding the risks can be eliminated. If your bitcoins do end up lost or stolen then there's almost certainly nothing that can be done to get them back.

'''tl;dr''' The best way to store bitcoin is to either use a [[hardware wallet]], a [[Multi-signature|multi-signature wallet]] or a [[Cold storage|cold storage wallet]]. Have your wallet create a [[seed phrase]], write it down on paper and store it in a safe place (or several safe places, as backups). Ideally the wallet should be backed by your own [[full node]].

== Introduction ==

Storage of bitcoin can be broken down in a few independent goals:

* Protection against accidental loss
* Verification that the bitcoins are genuine
* Privacy and protection against spying
* Protection against theft
* Easy access for spending or moving bitcoins

The art and science of storing bitcoins is about keeping your private keys safe, yet remaining easily available to you when you want to make a transaction. It also requires verifying that you received real bitcoins, and stopping an adversary from spying on you.

[[File:Mnemonic-seed-still-life.jpg|300px|thumb|alt=An example seed phrase written on paper|Example seed phrase on paper.]]

=== Protection from accidental loss ===

In the past many people have accidentally lost bitcoins because of failed backups, mistyped letters, forgotten hard drives, corrupted SSD devices, or numerous other slip ups.

The key to protecting yourself from data loss of any kind is to have redundant backups so that if one is lost or destroyed, you still have others you can use when you need them. All good wallet software asks their users to write down the [[seed phrase|seed recovery phrase]] of the wallet as a backup, so that if your primary wallet is lost or damaged, you can use the seed recovery phrase to restore access to your coins. If you have more than one backup location, they should be in places where various disasters won't affect both of your backups. For example, its much better to store two backups in a home safe and in a safe deposit box (as long as your seed is protected by a passphrase) than to store two backups in your bedroom and one in your garage.

Also important is regularly verifying that your backup still exists and is in good condition. This can be as simple as ensuring your backups are still where you put them a couple times a year.

The best practices for backing up a seed is to store the seed using '''pencil and paper''' or '''metal seed phrase backup''' and storing in multiple secure locations. See [[Seed_phrase#Storing_Seed_Phrases_for_the_Long_Term]] for details.

=== Verification and privacy ===

Storing a [[seed phrase]] only stores [[Private key|private keys]], but it cannot tell you if or how many bitcoins you have actually received. For that you need wallet software.

If you received cash banknotes or gold coins as payment, you wouldn't accept them without inspecting them and verifying that they are genuine. The same is true with bitcoin. Wallet software can automatically verify that a payment has been made and when that payment has been completed (by being mined into a number of blocks). The most secure kind of wallet is one which independently verifies ''all'' the rules of bitcoin, known as a [[full node]]. When receiving large volumes, it is essential to use wallet software that connects to a full node you run yourself. If bitcoin is digital gold, then a full node is your own personal digital goldsmith who checks that received bitcoin payments are actually real. [[Lightweight node|Lightweight wallets]] have a number of security downsides because they don't check all of bitcoin's rules, and so should only be used for receiving smaller amounts or when you trust the sender. See the article about [[full node|full nodes]].

Your wallet software will also need to learn the history and balance of its wallet. For a lightweight wallet this usually involves querying a third-party server which leads to a privacy problem as that server can spy on you by seeing your entire balance, all your transactions and usually linking it with your IP address. Using a full node avoids this problem because the software connects directly to the bitcoin p2p network and downloads the entire [[blockchain]], so any adversary will find it much harder to obtain information. See also: [[Anonymity]]

So for verification and privacy, a good storage solution should be backed by a [[full node]] under your own control for use when receiving payments. The full node wallet on an online computer can be a watch-only wallet. This means that it can detect transaction involving addresses belonging to the user and can display transaction information about them, but still does not have the ability to actually spend the bitcoins.

=== Protection from theft ===

Possession of bitcoins comes from your ability to keep the private keys under your exclusive control. In bitcoin, keys are money. Any malware or hackers who learn what your private keys are can create a valid bitcoin transaction sending your coins to themselves, stealing your bitcoins. The average person's computer is usually vulnerable to malware, so that must be taken into account when deciding on storage solutions.

Anybody else who discovers a wallet's [[seed phrase]] can steal all the bitcoins if the seed isn't also protected by a secret passphrase. Even when using a passphrase, a seed should be kept safe and secret like jewels or cash. For example, no part of a seed should ever be typed into any website, and no one should store a seed on an internet-connected computer unless they are an advanced user who has researched what they're doing.

[[Seed phrase]]s can store any amount of bitcoins. It doesn't seem secure to possibly have enough money to purchase the entire building just sitting on a sheet of paper without any protection. For this reason many wallets make it possible to encrypt a seed phrase with a passphrase. See [[Seed phrase#Two-Factor_Seed_Phrases]]

=== Easy access ===

Some users may not need to actually move their bitcoins very often, especially if they [[Bitcoin as an investment|own bitcoin as an investment]]. Other users will want to be able to quickly and easily move their coins. A solution for storing bitcoins should take into account how convenient it is to spend from depending on the user's needs.

=== Summary ===

In summary: bitcoin wallets should be backed up by writing down their [[seed phrase]], this phrase must be kept safe and secret, and when sending or receiving transactions the wallet software should obtain information about the bitcoin network from your own [[full node]].

== Types of wallets ==

=== Hardware wallets ===

''Main article: [[Hardware wallet]]''

[[Hardware wallet]]s are special purpose security-hardened devices for storing Bitcoins on a peripheral that is trusted to generate wallet keys and sign transactions.

A [[hardware wallet]] holds the seed in its internal storage and is typically designed to be resistant to both physical and digital attacks. The device signs the transactions internally and only transmits the signed transactions to the computer, never communicating any secret data to the devices it connects to. The separation of the private keys from the vulnerable environment allows the user to spend bitcoins without running any risk even when using an untrustworthy computer. Hardware wallets are relatively user-friendly and are one of the best ways to store bitcoins.

Some downsides are that hardware wallets are recognizable physical objects which could be discovered and which give away that you probably own bitcoins. This is worth considering when for example crossing borders. They also cost more than software wallets. Still, physical access to a hardware wallet does not mean that the keys are easily compromised, even though it does make it easier to compromise the hardware wallet. The groups that have created the most popular hardware wallets have gone to great lengths to harden the devices to physical threats and, though not impossible, only technically skilled people with specialized equipment have been able to get access to the private keys without the owner's consent. However, physically-powerful people such as armed border guards upon seeing the hardware wallet could force you to type in the PIN number to unlock the device and steal the bitcoins.

=== Multi-signature wallets ===

''Main article: [[Multi-signature]]''

A multi-signature wallet is one where multiple private keys are required to move the bitcoins instead of a single key. Such a wallet can be used for requiring agreement among multiple people to spend, can eliminate a single point of failure, and can be used as form of backup, among other applications.

These private keys can be spread across multiple machines in various locations with the rationale that malware and hackers are unlikely to infect all of them. The multisig wallet can be of the m-of-n type where any m private keys out of a possible n are required to move the money. For example a 2-of-3 multisig wallet might have your private keys spread across a desktop, laptop, and smartphone, any two of which are required to move the money, but the compromise or total loss of any one key does not result in loss of money, even if that key has no backups.

Multi-signature wallets have the advantage of being cheaper than hardware wallets since they are implemented in software and can be downloaded for free, and can be nearly as convenient since all keys are online and the wallet user interfaces are typically easy to use.

Hardware and multi-signature wallets can be combined by having a multi-signature wallet with the private keys held on hardware wallets; after all a single hardware wallet is still a single point of failure. Cold storage and multi-signature can also be combined, by having the multi-signature wallet with the private keys held in cold storage to avoid them being kept online.

=== Cold storage wallets ===

''Main article: [[Cold storage]]''

A cold wallet generates and stores private wallet keys offline on a clean, newly-installed [https://en.wikipedia.org/wiki/Air_gap_(networking) air-gapped] computer. Payments are received online with a watch-only wallet. Unsigned transactions are generated online, transferred offline for signing, and the signed transaction is transferred online to be broadcast to the Bitcoin network.

This allows funds to be managed offline in [[Cold storage]]. Used correctly a cold wallet is protected against online threats, such as viruses and hackers. Cold wallets are similar to hardware wallets, except that a general purpose computing device is used instead of a special purpose peripheral. The downside is that the transferring of transactions to and fro can be fiddly and unweilding, and less practical for carrying around like a hardware wallet.

=== Hot wallets ===

''Main article: [[Hot wallet]]''

A hot wallet refers to keeping single-signature wallets with private keys kept on an online computer or mobile phone. Most bitcoin wallet software out there is a hot wallet. The bitcoins are easy to spend but are maximally vulnerable to malware or hackers. Hot wallets may be appropriate for small amounts and day-to-day spending.

A user might have a ''spending account'' hot wallet for day-to-day convenient spending with the majority of their funds on a ''savings account'' which is stored with much more security (cold storage / hardware wallet / multi-signature).

== Bad wallet ideas ==

=== Custodial wallets ===

Custodial wallets are where an exchange, broker or other third party holds your bitcoins in trust.

The number one rule to storing bitcoin is this: if you don’t hold the private keys, you don’t actually own the assets. There are many historical examples of loss due to custodial wallets: Bitcoinica, Silk Road, Bitfloor, [[Collapse of Mt. Gox|MTGOX]], Sheep Marketplace, BTC-e, Bitstamp, Bitfinex, Bithumb, Cryptsy, [[BTER|Bter]], Mintpal and many more<ref>https://bitcointalk.org/index.php?topic=576337</ref>

==== "Isn't it just like keeping your money in a bank?" ====

''The following is a quote of waxwing on reddit<ref>https://www.reddit.com/r/Bitcoin/comments/5py495/brian_armstrong_controlling_your_own_wealth_as_a/dcve9xx/?context=3</ref>:''

:There are trade offs with everything, but trusting Coinbase with your Bitcoin is ''not'' the same as trusting a bank with your dollars:

:Suppose 5 people are needed to access the funds, within Coinbase, e.g. the CEO, the tech lead engineer and 3 other senior employees. Suppose one day they wake up and decide to be evil and move all the Bitcoin to some private account of theirs, and perhaps make up a story in the press about how they've been "hacked". You have a serious problem, as you might find there is a protracted legal battle (see MtGox), but you can't actually retrieve the funds unless in some way the company is re-stocked with Bitcoin, or perhaps an equivalent in fiat.

:If on the other hand you controlled the funds with a majority of keys in a multisig i.e. you own both of the two needed keys of a 2-of-3 multisig, then it would always effectively be your bitcoin, even though the third key may belong to a trusted third party custodian. But this also comes with the responsibility that if you get hacked, you lose all your funds. That is why it's prudent, in a 2-of-3 multisig where you have the two needed keys, to have them in separate systems/locations. If one of them fails, you can go to the custodian to supply the third key and transfer your funds again to safety. But the custodian alone, cannot touch your funds just by virtue of having the third key.

:Now, if your bank gets hacked similarly - 5 key operatives in the bank decide to swipe your money and pretend it was external hackers - SWIFT transfers are made to accounts in Russia and China. Here it will always ultimately be at the discretion of legal agencies whether you "actually" still have the money that is stolen. Because dollars are not real, they can be created at a whim<ref>https://en.wikipedia.org/wiki/Fractional-reserve_banking</ref>, and while reversing international transfers is not ''quite'' so simple, very often that reversal can be achieved (e.g. recent SWIFT hack at bangladesh<ref>https://www.wired.com/2016/05/insane-81m-bangladesh-bank-heist-heres-know/</ref><ref>https://en.wikipedia.org/wiki/Bangladesh_Bank_robbery</ref> bank; $1 billion stolen, all but $80 million "recovered" (just means wire transfers reversed)). Added to that consider that fiat money is insured, so even when transfers can't be reversed, the money can be "recovered". If too many banks get hacked all at once the Federal Reserve and the government together can make up some "fund" that magically reassigns balances any time they like, with sufficient political will (that's essentially what was happening in 2008 TARP etc).

:So far no insurance company has ever paid out on a Bitcoin company's claim. Worth considering also.

:You might say, since it's risky both ways, why not trust Coinbase? Aren't they more competent in security than me?

:Almost certainly, but this argument has two massive holes in it: (1) because they ''concentrate'' funds they are a massive target for hackers, while you are not - at all. (2) they are a ''trusted third party'' so the situation is strictly worse - not only do you have to trust their security skills, but you also have to trust them not to steal (modulo multisig, as mentioned above) (edited to add: as well as literal stealing, there is things like political confiscation, don't forget).

=== Web wallets ===

Web wallets have all the downsides of custodial wallets (no direct possession, private keys are held by a third party) along with all the downsides of hot wallets (exposed private keys), as well as all the downsides of lightweight wallets (not verifying bitcoin's rules, someone could send you a billion bitcoins and under certain conditions the dumb web wallet would happily accept it)

Someone who needs the easy access of a web wallet should download a lightweight wallet like [[Electrum]].

Main article: [[Browser-based wallet]]

=== Paper wallets ===

So-called [[paper wallets]] are an obsolete and unsafe method of storing bitcoin which should not be recommended to beginners. They simply store a single private/public keypair on paper. They promote [[address reuse]] and require unwieldy and complicated live OS system boots to be safe, they risk theft by printers, and typically rely on [[Javascript cryptography]].

Paper wallets also do not provide any method of displaying to the user when money has arrived. There's no practical way to use a [[full node]] wallet. Users are typically driven to use third-party blockchain explorers which can lie to them and spy on them.

A much better way to accomplish what paper wallets do is to use [[seed phrase]]s instead.

Main article: [[Paper wallets]]

=== Brain wallets ===

Brain wallets are an old type of wallet format which was very common to use in the early 2010s. It involves generating a password and then performing single SHA256 hash to obtain a bitcoin private key to use for transactions. The password is supposed to be memorized in your head, and not written down. The main advantage of wallet type is its ease of remembering the private key. However, this is eclipsed by its many drawbacks. Cybercriminals have wiped clean most brain wallets using GPU farms and password generation tools. It is also easier for an amateur hacker to steal funds contained inside a brain wallet if the password was sloppily chosen. Additionally, if you forget the password at any point, you might permanently lose access to your coins.

Main article: [[Brainwallet]]

=== Cloud storage ===

This means storing your encrypted (or not) wallet file on a cloud storage solution such as Dropbox, or emailing them to yourself on gmail. This very similar to trusting a custodial wallet service, and is not recommended for the same reasons<ref>https://www.reddit.com/r/Bitcoin/comments/8i6via/28_btc_stolen_10_btc_reward_please_help/</ref>. You might say you use encryption for two-factor authentication, but uploading the wallet to the cloud reduces this to one-factor. Furthermore, there are a variety of ways in which 2FA can be compromised, in particular SMS-based 2FA, such as via a SIM-Swap.

=== Removable media ===

This refers to storing wallet files on removable media like SSD or hard drives.

Refer to the warnings from these two links:

* https://www.reddit.com/r/Bitcoin/comments/6nj0eb/reminder_beware_of_data_rot_always_make_paper/

Those articles recommend using GPG for encryption or a printer, instead a better solution is [[seed phrase]]s.

=== "Physical" Bitcoins ===

Physical Coins and other mechanism with a pre-manufactured key or seed are not a good way to store bitcoins because they keys are already potentially compromised by whoever created the key. You should not consider bitcoin yours if its stored on a key created by someone else. It only becomes yours when you transfer the bitcoin to a key that you own and exclusively control.

== Other ideas ==

=== Time-locked wallets ===

An interesting unconventional solution. The idea is to use [[Timelock|time-lock contracts]] to create a wallet which cannot be spent from until a certain date. One possible use-case might be by a gambling addict who locks up money for paying bills for a month, after a month has passed and their time-lock wallet is opened they use that money for paying bills instead of gambling. This is the equivalent proposal towards compulsive shoppers to freeze their credit card in a block of ice, so when they feel the urge to immediately buy something they see on the TV, they will need to wait for the block to melt until they can retrieve the credit card to be able to place the order. This hopefully gives them the time to cool off, and reconsider an otherwise meaningless purchase.

Time lock wallets don't exist yet except for simple [https://coinb.in/#newTimeLocked javascript pages] which rely on [[Javascript cryptography]] and are therefore not safe.

=== Consulting ===

If you intend to store a very large amount of bitcoins, for example in a business, you should consider paying for security consulting.

== The 5 dollar wrench attack ==

[[File:Security.png|400px|none|alt=xkcd comic on the 5 dollar wrench attack.]]

It's sometimes said that all this security is worthless because the $5 wrench attack can be used.

There are multiple ways that can be utilized to beat this attack: by hiding, by defending yourself, by not letting others know your Bitcoin wealth or holdings, or by implementing security procedures which would prevent you from being able to surrender funds in such an attack, thereby reducing the appeal for an attacker to perform such an attack in the first place.

Stored bitcoins are not secured by [[seed phrase]]s, [[hardware wallet]]s, [[multi-signature]], passwords, hash functions or anything like that; they are secured by ''people''.

Technology is never the root of system security. Technology is a tool to help people secure what they value. Security requires people to act. A server cannot be secured by a firewall if there is no lock on the door to the server room, and a lock cannot secure the server room without a guard to monitor the door, and a guard cannot secure the door without risk of personal harm.<ref>[https://github.com/libbitcoin/libbitcoin/wiki/Risk-Sharing-Principle Libbitcoin wiki Risk Sharing Principle]</ref>.

Bitcoin is no different. The technology discussed on this page is only a tool to tip the scales in the defender's favour. Following from this principle, the way to beat the $5 wrench attack is to bear arms. Either your own, or employ guards, or use a safety deposit box, or rely on the police forces and army; or whatever may be appropriate and proportionate in your situation. If someone physically overpowers you then no technology on Earth can save your bitcoins. You can't be your own bank without bank-level security.

See Also: [https://www.youtube.com/watch?v=H16Zus3GAVA Advice by a former police officer about physical security in bitcoin]

== See also ==

* [[Links to Storage Methods]]

== Further reading ==

* [https://github.com/BlockchainCommons/SmartCustodyWhitePapers/blob/master/%23SmartCustody-_Simple_Self-Custody_Cold_Storage_Scenario.md SmartCustody: Simple Self-Custody Cold Storage Scenario]

* https://medium.com/@michaelflaxman/how-should-i-store-my-bitcoin-43874ac208e4

* Two-factor authentication on custodial wallets doesn't work as well as you might think https://medium.com/@CodyBrown/how-to-lose-8k-worth-of-bitcoin-in-15-minutes-with-verizon-and-coinbase-com-ba75fb8d0bac

* This is why you shouldn’t use SMS for two-factor authentication https://www.theverge.com/2017/9/18/16328172/sms-two-factor-authentication-hack-password-bitcoin Hacking 2FA based on SMS is easy.

* [[Backup and Storage Methods]]

==References==
<references />

[[Category:Security]]
[[Category:Wallets| ]]

Storing bitcoins

2025-12-19T14:14:51Z

NotATether: Add brain wallets

''This page is a discussion of the different ways of storing bitcoins, whether for [[Bitcoin as an investment|investment purposes]] or as a [[Bitcoin as a medium of exchange|medium of exchange]].''

As bitcoin is a digital asset, it can be very un-intuitive to store safely. Historically many people have lost their coins but with proper understanding the risks can be eliminated. If your bitcoins do end up lost or stolen then there's almost certainly nothing that can be done to get them back.

'''tl;dr''' The best way to store bitcoin is to either use a [[hardware wallet]], a [[Multi-signature|multi-signature wallet]] or a [[Cold storage|cold storage wallet]]. Have your wallet create a [[seed phrase]], write it down on paper and store it in a safe place (or several safe places, as backups). Ideally the wallet should be backed by your own [[full node]].

== Introduction ==

Storage of bitcoin can be broken down in a few independent goals:

* Protection against accidental loss
* Verification that the bitcoins are genuine
* Privacy and protection against spying
* Protection against theft
* Easy access for spending or moving bitcoins

The art and science of storing bitcoins is about keeping your private keys safe, yet remaining easily available to you when you want to make a transaction. It also requires verifying that you received real bitcoins, and stopping an adversary from spying on you.

[[File:Mnemonic-seed-still-life.jpg|300px|thumb|alt=An example seed phrase written on paper|Example seed phrase on paper.]]

=== Protection from accidental loss ===

In the past many people have accidentally lost bitcoins because of failed backups, mistyped letters, forgotten hard drives, corrupted SSD devices, or numerous other slip ups.

The key to protecting yourself from data loss of any kind is to have redundant backups so that if one is lost or destroyed, you still have others you can use when you need them. All good wallet software asks their users to write down the [[seed phrase|seed recovery phrase]] of the wallet as a backup, so that if your primary wallet is lost or damaged, you can use the seed recovery phrase to restore access to your coins. If you have more than one backup location, they should be in places where various disasters won't affect both of your backups. For example, its much better to store two backups in a home safe and in a safe deposit box (as long as your seed is protected by a passphrase) than to store two backups in your bedroom and one in your garage.

Also important is regularly verifying that your backup still exists and is in good condition. This can be as simple as ensuring your backups are still where you put them a couple times a year.

The best practices for backing up a seed is to store the seed using '''pencil and paper''' or '''metal seed phrase backup''' and storing in multiple secure locations. See [[Seed_phrase#Storing_Seed_Phrases_for_the_Long_Term]] for details.

=== Verification and privacy ===

Storing a [[seed phrase]] only stores [[Private key|private keys]], but it cannot tell you if or how many bitcoins you have actually received. For that you need wallet software.

If you received cash banknotes or gold coins as payment, you wouldn't accept them without inspecting them and verifying that they are genuine. The same is true with bitcoin. Wallet software can automatically verify that a payment has been made and when that payment has been completed (by being mined into a number of blocks). The most secure kind of wallet is one which independently verifies ''all'' the rules of bitcoin, known as a [[full node]]. When receiving large volumes, it is essential to use wallet software that connects to a full node you run yourself. If bitcoin is digital gold, then a full node is your own personal digital goldsmith who checks that received bitcoin payments are actually real. [[Lightweight node|Lightweight wallets]] have a number of security downsides because they don't check all of bitcoin's rules, and so should only be used for receiving smaller amounts or when you trust the sender. See the article about [[full node|full nodes]].

Your wallet software will also need to learn the history and balance of its wallet. For a lightweight wallet this usually involves querying a third-party server which leads to a privacy problem as that server can spy on you by seeing your entire balance, all your transactions and usually linking it with your IP address. Using a full node avoids this problem because the software connects directly to the bitcoin p2p network and downloads the entire [[blockchain]], so any adversary will find it much harder to obtain information. See also: [[Anonymity]]

So for verification and privacy, a good storage solution should be backed by a [[full node]] under your own control for use when receiving payments. The full node wallet on an online computer can be a watch-only wallet. This means that it can detect transaction involving addresses belonging to the user and can display transaction information about them, but still does not have the ability to actually spend the bitcoins.

=== Protection from theft ===

Possession of bitcoins comes from your ability to keep the private keys under your exclusive control. In bitcoin, keys are money. Any malware or hackers who learn what your private keys are can create a valid bitcoin transaction sending your coins to themselves, stealing your bitcoins. The average person's computer is usually vulnerable to malware, so that must be taken into account when deciding on storage solutions.

Anybody else who discovers a wallet's [[seed phrase]] can steal all the bitcoins if the seed isn't also protected by a secret passphrase. Even when using a passphrase, a seed should be kept safe and secret like jewels or cash. For example, no part of a seed should ever be typed into any website, and no one should store a seed on an internet-connected computer unless they are an advanced user who has researched what they're doing.

[[Seed phrase]]s can store any amount of bitcoins. It doesn't seem secure to possibly have enough money to purchase the entire building just sitting on a sheet of paper without any protection. For this reason many wallets make it possible to encrypt a seed phrase with a passphrase. See [[Seed phrase#Two-Factor_Seed_Phrases]]

=== Easy access ===

Some users may not need to actually move their bitcoins very often, especially if they [[Bitcoin as an investment|own bitcoin as an investment]]. Other users will want to be able to quickly and easily move their coins. A solution for storing bitcoins should take into account how convenient it is to spend from depending on the user's needs.

=== Summary ===

In summary: bitcoin wallets should be backed up by writing down their [[seed phrase]], this phrase must be kept safe and secret, and when sending or receiving transactions the wallet software should obtain information about the bitcoin network from your own [[full node]].

== Types of wallets ==

=== Hardware wallets ===

''Main article: [[Hardware wallet]]''

[[Hardware wallet]]s are special purpose security-hardened devices for storing Bitcoins on a peripheral that is trusted to generate wallet keys and sign transactions.

A [[hardware wallet]] holds the seed in its internal storage and is typically designed to be resistant to both physical and digital attacks. The device signs the transactions internally and only transmits the signed transactions to the computer, never communicating any secret data to the devices it connects to. The separation of the private keys from the vulnerable environment allows the user to spend bitcoins without running any risk even when using an untrustworthy computer. Hardware wallets are relatively user-friendly and are one of the best ways to store bitcoins.

Some downsides are that hardware wallets are recognizable physical objects which could be discovered and which give away that you probably own bitcoins. This is worth considering when for example crossing borders. They also cost more than software wallets. Still, physical access to a hardware wallet does not mean that the keys are easily compromised, even though it does make it easier to compromise the hardware wallet. The groups that have created the most popular hardware wallets have gone to great lengths to harden the devices to physical threats and, though not impossible, only technically skilled people with specialized equipment have been able to get access to the private keys without the owner's consent. However, physically-powerful people such as armed border guards upon seeing the hardware wallet could force you to type in the PIN number to unlock the device and steal the bitcoins.

=== Multi-signature wallets ===

''Main article: [[Multi-signature]]''

A multi-signature wallet is one where multiple private keys are required to move the bitcoins instead of a single key. Such a wallet can be used for requiring agreement among multiple people to spend, can eliminate a single point of failure, and can be used as form of backup, among other applications.

These private keys can be spread across multiple machines in various locations with the rationale that malware and hackers are unlikely to infect all of them. The multisig wallet can be of the m-of-n type where any m private keys out of a possible n are required to move the money. For example a 2-of-3 multisig wallet might have your private keys spread across a desktop, laptop, and smartphone, any two of which are required to move the money, but the compromise or total loss of any one key does not result in loss of money, even if that key has no backups.

Multi-signature wallets have the advantage of being cheaper than hardware wallets since they are implemented in software and can be downloaded for free, and can be nearly as convenient since all keys are online and the wallet user interfaces are typically easy to use.

Hardware and multi-signature wallets can be combined by having a multi-signature wallet with the private keys held on hardware wallets; after all a single hardware wallet is still a single point of failure. Cold storage and multi-signature can also be combined, by having the multi-signature wallet with the private keys held in cold storage to avoid them being kept online.

=== Cold storage wallets ===

''Main article: [[Cold storage]]''

A cold wallet generates and stores private wallet keys offline on a clean, newly-installed [https://en.wikipedia.org/wiki/Air_gap_(networking) air-gapped] computer. Payments are received online with a watch-only wallet. Unsigned transactions are generated online, transferred offline for signing, and the signed transaction is transferred online to be broadcast to the Bitcoin network.

This allows funds to be managed offline in [[Cold storage]]. Used correctly a cold wallet is protected against online threats, such as viruses and hackers. Cold wallets are similar to hardware wallets, except that a general purpose computing device is used instead of a special purpose peripheral. The downside is that the transferring of transactions to and fro can be fiddly and unweilding, and less practical for carrying around like a hardware wallet.

=== Hot wallets ===

''Main article: [[Hot wallet]]''

A hot wallet refers to keeping single-signature wallets with private keys kept on an online computer or mobile phone. Most bitcoin wallet software out there is a hot wallet. The bitcoins are easy to spend but are maximally vulnerable to malware or hackers. Hot wallets may be appropriate for small amounts and day-to-day spending.

A user might have a ''spending account'' hot wallet for day-to-day convenient spending with the majority of their funds on a ''savings account'' which is stored with much more security (cold storage / hardware wallet / multi-signature).

== Bad wallet ideas ==

=== Custodial wallets ===

Custodial wallets are where an exchange, broker or other third party holds your bitcoins in trust.

The number one rule to storing bitcoin is this: if you don’t hold the private keys, you don’t actually own the assets. There are many historical examples of loss due to custodial wallets: Bitcoinica, Silk Road, Bitfloor, [[Collapse of Mt. Gox|MTGOX]], Sheep Marketplace, BTC-e, Bitstamp, Bitfinex, Bithumb, Cryptsy, [[BTER|Bter]], Mintpal and many more<ref>https://bitcointalk.org/index.php?topic=576337</ref>

==== "Isn't it just like keeping your money in a bank?" ====

''The following is a quote of waxwing on reddit<ref>https://www.reddit.com/r/Bitcoin/comments/5py495/brian_armstrong_controlling_your_own_wealth_as_a/dcve9xx/?context=3</ref>:''

:There are trade offs with everything, but trusting Coinbase with your Bitcoin is ''not'' the same as trusting a bank with your dollars:

:Suppose 5 people are needed to access the funds, within Coinbase, e.g. the CEO, the tech lead engineer and 3 other senior employees. Suppose one day they wake up and decide to be evil and move all the Bitcoin to some private account of theirs, and perhaps make up a story in the press about how they've been "hacked". You have a serious problem, as you might find there is a protracted legal battle (see MtGox), but you can't actually retrieve the funds unless in some way the company is re-stocked with Bitcoin, or perhaps an equivalent in fiat.

:If on the other hand you controlled the funds with a majority of keys in a multisig i.e. you own both of the two needed keys of a 2-of-3 multisig, then it would always effectively be your bitcoin, even though the third key may belong to a trusted third party custodian. But this also comes with the responsibility that if you get hacked, you lose all your funds. That is why it's prudent, in a 2-of-3 multisig where you have the two needed keys, to have them in separate systems/locations. If one of them fails, you can go to the custodian to supply the third key and transfer your funds again to safety. But the custodian alone, cannot touch your funds just by virtue of having the third key.

:Now, if your bank gets hacked similarly - 5 key operatives in the bank decide to swipe your money and pretend it was external hackers - SWIFT transfers are made to accounts in Russia and China. Here it will always ultimately be at the discretion of legal agencies whether you "actually" still have the money that is stolen. Because dollars are not real, they can be created at a whim<ref>https://en.wikipedia.org/wiki/Fractional-reserve_banking</ref>, and while reversing international transfers is not ''quite'' so simple, very often that reversal can be achieved (e.g. recent SWIFT hack at bangladesh<ref>https://www.wired.com/2016/05/insane-81m-bangladesh-bank-heist-heres-know/</ref><ref>https://en.wikipedia.org/wiki/Bangladesh_Bank_robbery</ref> bank; $1 billion stolen, all but $80 million "recovered" (just means wire transfers reversed)). Added to that consider that fiat money is insured, so even when transfers can't be reversed, the money can be "recovered". If too many banks get hacked all at once the Federal Reserve and the government together can make up some "fund" that magically reassigns balances any time they like, with sufficient political will (that's essentially what was happening in 2008 TARP etc).

:So far no insurance company has ever paid out on a Bitcoin company's claim. Worth considering also.

:You might say, since it's risky both ways, why not trust Coinbase? Aren't they more competent in security than me?

:Almost certainly, but this argument has two massive holes in it: (1) because they ''concentrate'' funds they are a massive target for hackers, while you are not - at all. (2) they are a ''trusted third party'' so the situation is strictly worse - not only do you have to trust their security skills, but you also have to trust them not to steal (modulo multisig, as mentioned above) (edited to add: as well as literal stealing, there is things like political confiscation, don't forget).

=== Web wallets ===

Web wallets have all the downsides of custodial wallets (no direct possession, private keys are held by a third party) along with all the downsides of hot wallets (exposed private keys), as well as all the downsides of lightweight wallets (not verifying bitcoin's rules, someone could send you a billion bitcoins and under certain conditions the dumb web wallet would happily accept it)

Someone who needs the easy access of a web wallet should download a lightweight wallet like [[Electrum]].

Main article: [[Browser-based wallet]]

=== Paper wallets ===

So-called [[paper wallets]] are an obsolete and unsafe method of storing bitcoin which should not be recommended to beginners. They simply store a single private/public keypair on paper. They promote [[address reuse]] and require unwieldy and complicated live OS system boots to be safe, they risk theft by printers, and typically rely on [[Javascript cryptography]].

Paper wallets also do not provide any method of displaying to the user when money has arrived. There's no practical way to use a [[full node]] wallet. Users are typically driven to use third-party blockchain explorers which can lie to them and spy on them.

A much better way to accomplish what paper wallets do is to use [[seed phrase]]s instead.

Main article: [[Paper wallets]]

=== Brain wallets ===

Brain wallets are an old type of wallet format which was very common to use in the early 2010s. It involves generating a password and then performing single SHA256 hash to obtain a bitcoin private key to use for transactions. The main advantage of wallet type is its ease of remembering the private key. However, this is eclipsed by its many drawbacks. Cybercriminals have wiped clean most brain wallets using GPU farms and password generation tools. It is also easier for an amateur hacker to steal funds contained inside a brain wallet if the password was sloppily chosen.

Main article: [[Brainwallet]]

=== Cloud storage ===

This means storing your encrypted (or not) wallet file on a cloud storage solution such as Dropbox, or emailing them to yourself on gmail. This very similar to trusting a custodial wallet service, and is not recommended for the same reasons<ref>https://www.reddit.com/r/Bitcoin/comments/8i6via/28_btc_stolen_10_btc_reward_please_help/</ref>. You might say you use encryption for two-factor authentication, but uploading the wallet to the cloud reduces this to one-factor. Furthermore, there are a variety of ways in which 2FA can be compromised, in particular SMS-based 2FA, such as via a SIM-Swap.

=== Removable media ===

This refers to storing wallet files on removable media like SSD or hard drives.

Refer to the warnings from these two links:

* https://www.reddit.com/r/Bitcoin/comments/6nj0eb/reminder_beware_of_data_rot_always_make_paper/

Those articles recommend using GPG for encryption or a printer, instead a better solution is [[seed phrase]]s.

=== "Physical" Bitcoins ===

Physical Coins and other mechanism with a pre-manufactured key or seed are not a good way to store bitcoins because they keys are already potentially compromised by whoever created the key. You should not consider bitcoin yours if its stored on a key created by someone else. It only becomes yours when you transfer the bitcoin to a key that you own and exclusively control.

== Other ideas ==

=== Time-locked wallets ===

An interesting unconventional solution. The idea is to use [[Timelock|time-lock contracts]] to create a wallet which cannot be spent from until a certain date. One possible use-case might be by a gambling addict who locks up money for paying bills for a month, after a month has passed and their time-lock wallet is opened they use that money for paying bills instead of gambling. This is the equivalent proposal towards compulsive shoppers to freeze their credit card in a block of ice, so when they feel the urge to immediately buy something they see on the TV, they will need to wait for the block to melt until they can retrieve the credit card to be able to place the order. This hopefully gives them the time to cool off, and reconsider an otherwise meaningless purchase.

Time lock wallets don't exist yet except for simple [https://coinb.in/#newTimeLocked javascript pages] which rely on [[Javascript cryptography]] and are therefore not safe.

=== Consulting ===

If you intend to store a very large amount of bitcoins, for example in a business, you should consider paying for security consulting.

== The 5 dollar wrench attack ==

[[File:Security.png|400px|none|alt=xkcd comic on the 5 dollar wrench attack.]]

It's sometimes said that all this security is worthless because the $5 wrench attack can be used.

There are multiple ways that can be utilized to beat this attack: by hiding, by defending yourself, by not letting others know your Bitcoin wealth or holdings, or by implementing security procedures which would prevent you from being able to surrender funds in such an attack, thereby reducing the appeal for an attacker to perform such an attack in the first place.

Stored bitcoins are not secured by [[seed phrase]]s, [[hardware wallet]]s, [[multi-signature]], passwords, hash functions or anything like that; they are secured by ''people''.

Technology is never the root of system security. Technology is a tool to help people secure what they value. Security requires people to act. A server cannot be secured by a firewall if there is no lock on the door to the server room, and a lock cannot secure the server room without a guard to monitor the door, and a guard cannot secure the door without risk of personal harm.<ref>[https://github.com/libbitcoin/libbitcoin/wiki/Risk-Sharing-Principle Libbitcoin wiki Risk Sharing Principle]</ref>.

Bitcoin is no different. The technology discussed on this page is only a tool to tip the scales in the defender's favour. Following from this principle, the way to beat the $5 wrench attack is to bear arms. Either your own, or employ guards, or use a safety deposit box, or rely on the police forces and army; or whatever may be appropriate and proportionate in your situation. If someone physically overpowers you then no technology on Earth can save your bitcoins. You can't be your own bank without bank-level security.

See Also: [https://www.youtube.com/watch?v=H16Zus3GAVA Advice by a former police officer about physical security in bitcoin]

== See also ==

* [[Links to Storage Methods]]

== Further reading ==

* [https://github.com/BlockchainCommons/SmartCustodyWhitePapers/blob/master/%23SmartCustody-_Simple_Self-Custody_Cold_Storage_Scenario.md SmartCustody: Simple Self-Custody Cold Storage Scenario]

* https://medium.com/@michaelflaxman/how-should-i-store-my-bitcoin-43874ac208e4

* Two-factor authentication on custodial wallets doesn't work as well as you might think https://medium.com/@CodyBrown/how-to-lose-8k-worth-of-bitcoin-in-15-minutes-with-verizon-and-coinbase-com-ba75fb8d0bac

* This is why you shouldn’t use SMS for two-factor authentication https://www.theverge.com/2017/9/18/16328172/sms-two-factor-authentication-hack-password-bitcoin Hacking 2FA based on SMS is easy.

* [[Backup and Storage Methods]]

==References==
<references />

[[Category:Security]]
[[Category:Wallets| ]]

Bitcoin

2025-12-19T13:43:48Z

NotATether: remove commercial promotion

'''Bitcoin''' is a decentralized [[digital currency]] created by an unknown person or group of people under the name [[Satoshi Nakamoto]] and released as open-source software in 2009. It does not rely on a central server to process transactions or store funds. There are a maximum of 2,099,999,997,690,000 bitcoin elements (called satoshis, the unit has been named in collective homage to the original creator), which are currently most commonly measured in units of 100,000,000 known as BTC. There will only ever be 21 million bitcoin (BTC) to ever be created.

{{As of|January 2018}}, it is the most widely used alternative currency,<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph">{{cite web|title=Quantitative Analysis of the Full Bitcoin Transaction Graph|url=https://eprint.iacr.org/2012/584.pdf|publisher=Cryptology ePrint Archive|accessdate=18 October 2012|author=Ron Dorit|coauthors=Adi Shamir|page=17|quote=The Bitcoin system is the best known and most widely used alternative payment scheme,...}}</ref><ref name="Cryptocurrency Market Capitalization">{{Cite web|title=Coinmarketcap.com|url=https://coinmarketcap.com/}}</ref> now with the total market cap around 250 billion US dollars.<ref>{{cite web|title=Market Capitalization|url=https://coinmarketcap.com/currencies/bitcoin/|publisher=Coinmarketcap.com|accessdate=10 January 2018}}</ref>

Bitcoin has no central issuer; instead, the peer-to-peer network regulates bitcoins, transactions and issuance according to consensus in network software. These transactions are verified by network nodes through the use of cryptography and recorded in a public distributed ledger called a blockchain.

Bitcoins are issued to various nodes that verify transactions through computing power;
it is established that there will be a limited and scheduled release of no more than BTC 21 million worth of coins, which will be fully issued by the year 2140.

Bitcoins are created as a reward for a process known as mining. They can be exchanged for other currencies, products, and services. As of February 2015, over 100,000 merchants and vendors accepted bitcoins as payment. Research produced by the University of Cambridge estimates that in 2017, there were 2.9 to 5.8 million unique users using a cryptocurrency wallet, most of them using Bitcoin.

Internationally, bitcoins can be exchanged and managed through various websites and [[software]] along with physical banknotes and coins.<ref>{{Cite web|title=Physical Bitcoins by Casascius|url=https://www.casascius.com/|publisher=Casascius Coins|accessdate=29 September 2012}}</ref><ref>{{Cite web|title=Bitbills|url=http://www.bitbills.com/|publisher=Bitbills|accessdate=29 September 2012}}</ref>

==History==
{{main|History}}

A cryptographic system for untraceable payments was first described by David Chaum in 1982.<ref>[http://blog.koehntopp.de/uploads/Chaum.BlindSigForPayment.1982.PDF David Chaum, Blind signatures for untraceable payments], Advances in Cryptology - Crypto '82, Springer-Verlag (1983), 199–203.</ref> In 1990 Chaum extended this system to create the first cryptographic anonymous electronic cash system.,<ref>{{cite journal|journal=Lecture Notes in Computer Science|last1=Chaum|first1=David|last2=Fiat|first2=Amos|last3=Naor|first3=Moni|title=Untraceable Electronic Cash|url=http://blog.koehntopp.de/uploads/chaum_fiat_naor_ecash.pdf}}</ref> which became known as ecash.
<ref>{{cite web|url=https://www.wired.com/wired/archive/2.12/emoney.html|publisher=Wired|title=E-Money (That's What I Want)|date=1994–2012|author=Steven Levy}}</ref> In 1998 [[Wei Dai]] published a description of an anonymous, distributed electronic cash system which he called "b-money".<ref>{{cite web|title=B-Money|url=http://www.weidai.com/bmoney.txt|author=Wei Dai|year=1998}}</ref> Around the same time, Nick Szabo created ''bit gold''.<ref>{{cite web|url=https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0|title=Bitcoin: The Cryptoanarchists’ Answer to Cash|publisher=IEEE Spectrum|quote=Around the same time, Nick Szabo, a computer scientist who now blogs about law and the history of money, was one of the first to imagine a new digital currency from the ground up. Although many consider his scheme, which he calls “bit gold,” to be a precursor to Bitcoin}}</ref><ref name="bitgold">{{cite web|title=Bit gold|url=https://unenumerated.blogspot.co.uk/2005/12/bit-gold.html|author=Nick Szabo|quote=My proposal for bit gold is based on computing a string of bits from a string of challenge bits, using functions called variously "client puzzle function," "proof of work function," or "secure benchmark function.". The resulting string of bits is the proof of work.... The last-created string of bit gold provides the challenge bits for the next-created string.}}</ref> Like Bitcoin, ''Bit gold'' was a currency system where users would compete to solve a [[proof of work]] function, with solutions being cryptographically chained together and published via a distributed property title registry. A variant of ''Bit gold'', called ''Reusable Proofs of Work'', was implemented by Hal Finney.<ref name="bitgold"/>

In 2008, Satoshi Nakamoto published a [[Bitcoin_white_paper|paper]]<ref name="whitepaper">{{cite web
|last= Nakamoto
|first= Satoshi
|title= Bitcoin: A Peer-to-Peer Electronic Cash System
|url= http://www.cs.kent.edu/~JAVED/class-P2P12F/papers-2012/PAPER2012-p2p-bitcoin-satoshinakamoto.pdf
|accessdate = 14 December 2010
|date= 24 May 2009
|postscript=
}}</ref><ref>{{cite web
|url= https://article.gmane.org/gmane.comp.encryption.general/12588/
|title= Bitcoin P2P e-cash paper
}}</ref> on The Cryptography Mailing list at metzdowd.com<ref>[https://www.mail-archive.com/search?l=cryptography@metzdowd.com&q=from:%22Satoshi+Nakamoto%22 Satoshi's posts to Cryptography mailing list]</ref> describing the Bitcoin protocol.

The Bitcoin network came into existence on 3 January 2009 with the release of the first Bitcoin client, [[wxBitcoin]], and the issuance of the first bitcoins.<ref>{{cite web |title=Block 0 – Bitcoin Block Explorer |url=https://blockexplorer.com/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f }}</ref><ref>{{cite web |url=https://www.mail-archive.com/cryptography@metzdowd.com/msg10142.html |title=Bitcoin v0.1 released}}</ref><ref>{{cite web |url=https://sourceforge.net/news/?group_id=244765 |title=SourceForge.net: Bitcoin}}</ref>
A year after, the initial exchange rates for Bitcoin were set by individuals on the bitcointalk forums.{{Citation needed|date=October 2012}} The most significant transaction involved a BTC 10,000 pizza.<ref>{{cite web|title=The Rise and Fall of Bitcoin|url=https://www.wired.com/magazine/2011/11/mf_bitcoin/|publisher=Wired|accessdate=13 October 2012}}</ref>
Today, the majority of bitcoin exchanges occur on the [[Bitstamp]] bitcoin exchange.<ref>{{cite web | title = Exchange volume distribution | work = by market | publisher = [[Bitcoin Charts]] | date = 15 April 2014 | url = https://bitcoincharts.com/charts/volumepie/ | accessdate = 15 April 2014 }}</ref>

In 2011, Wikileaks,<ref>{{cite news
|last= Greenberg
|first= Andy
|url= http://blogs.forbes.com/andygreenberg/2011/06/14/wikileaks-asks-for-anonymous-bitcoin-donations/
|title= WikiLeaks Asks For Anonymous Bitcoin Donations – Andy Greenberg – The Firewall – Forbes
|publisher= Blogs.forbes.com
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> [[Freenet]],<ref>{{cite web
|url= https://freenetproject.org/donate.html
|title= /donate
|publisher= The Freenet Project
|date=
|accessdate = 22 June 2011
}}</ref> Singularity Institute,<ref>[http://singinst.org/donate/ SIAI donation page]</ref> Internet Archive,<ref>[https://www.archive.org/donate/index.php Internet Archive donation page]</ref> Free Software Foundation<ref>[https://my.fsf.org/donate/other/ Other ways to donate]</ref> and others, began [[Receiving_donations_with_bitcoin|to accept donations in bitcoins]]. The Electronic Frontier Foundation did so for a while but has since stopped, citing concerns about a lack of legal precedent about new currency systems, and because they "generally don't endorse any type of product or service".<ref>{{cite web
|url= https://www.eff.org/deeplinks/2011/06/eff-and-bitcoin
|title= EFF and Bitcoin | Electronic Frontier Foundation
|publisher= Eff.org
|date= 14 June 2011
|accessdate = 22 June 2011
}}</ref> Some small businesses had started to adopt Bitcoin. LaCie, a public company, accepts bitcoins for its Wuala service.<ref>{{Cite web|url=http://www.wuala.com/en/bitcoin |title=Secure Online Storage – Backup. Sync. Share. Access Everywhere |publisher=Wuala |date= |accessdate = 24 January 2012}}</ref>

In 2012, BitPay reports of having over 1000 merchants accepting bitcoins under its payment processing service.<ref>{{cite web|title=BitPay Signs 1,000 Merchants to Accept Bitcoin Payments|url=http://www.americanbanker.com/issues/177_176/bitpay-signs-1000-merchants-to-accept-bitcoin-payments-1052538-1.html|publisher=American Banker|accessdate=12 October 2012}}</ref>

==Administration==
Bitcoin is administered through a decentralized peer-to-peer network.<ref name="whitepaper"/> Cryptographic technologies and the peer-to-peer network of computing power enables users to make and verify irreversible, instant online bitcoin payments, without an obligation to trust and use centralized banking institutions and authorities. Dispute resolution services are not made directly available. Instead it is left to the users to verify and trust the parties they are sending money to through their choice of methods.

Bitcoins are issued according to rules agreed to by the majority of the computing power within the Bitcoin network. The core rules describing the predictable issuance of bitcoins to its verifying servers, a voluntary and competitive transaction fee system and the hard limit of no more than BTC 21 million issued in total.<ref name="whitepaper"/>

Bitcoin does not require a central bank, State,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/3
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> or incorporated backers.

==Services==
{{main|Wallet}}

Bitcoins are sent and received through software and websites called wallets. They send and confirm transactions to the network through Bitcoin addresses, the identifiers for users' Bitcoin wallets within the network.<ref name="whitepaper"/>

===Bitcoin addresses===
{{main|Address}}

Payments are made to Bitcoin "addresses": human-readable strings of numbers and letters around 33 characters in length, always beginning with the digit 1 or 3, as in the example of ''31uEbMgunupShBVTewXjtqbBv5MndwfXhb''.

Users obtain new Bitcoin addresses from their Bitcoin software. Creating a new address can be a completely offline process and require no communication with the Bitcoin network. Web services often generate a new Bitcoin address for every user, allowing them to have their custom deposit addresses.{{dubious}}

===Transaction fees===
{{main|Transaction fees}}
Transaction fees may be included with any transfer of bitcoins. While it's technically possible to send a transaction with zero fee, {{as of|2017|lc=on}} it's highly unlikely that one of these transactions confirms in a realistic amount of time, causing most nodes on the network to drop it. For transactions which consume or produce many outputs (and therefore have a large data size), higher transaction fees are usually expected.

===Confirmations===
{{main|Confirmation}}

The network's software confirms a transaction when it records it in a block. Further blocks of transactions confirm it even further. After six confirmations/blocks, a transaction is confirmed beyond reasonable doubt.

The network must store the whole transaction history inside the blockchain, which grows constantly as new records are added and never removed. Nakamoto conceived that as the database became larger, users would desire applications for Bitcoin that didn't store the entire database on their computer. To enable this, the blockchain uses a [[merkle tree]] to organize the transaction records in such a way that client software can locally delete portions of its own database it knows it will never need, such as earlier transaction records of bitcoins that have changed ownership multiple times.

==Economics==

===Initial distribution===

Bitcoin has no centralized issuing authority.<ref name="ars-06-08-11">
{{Cite news
|first= Thomas
|last= Lowenthal
|title= Bitcoin: inside the encrypted, peer-to-peer digital currency
|newspaper= Ars Technica
|date= 8 June 2011
|url= https://arstechnica.com/tech-policy/news/2011/06/bitcoin-inside-the-encrypted-peer-to-peer-currency.ars
}}</ref><ref>{{cite news
|author= Sponsored by
|url= http://www.economist.com/blogs/babbage/2011/06/virtual-currency
|title= Virtual currency: Bits and bob
|publisher= The Economist
|date=
|accessdate = 22 June 2011
}}</ref><ref>{{cite web
|last= Geere
|first= Duncan
|url= https://www.wired.co.uk/news/archive/2011-05/16/bitcoin-p2p-currency
|title= Peer-to-peer currency Bitcoin sidesteps financial institutions (Wired UK)
|publisher= Wired.co.uk
|date=
|accessdate = 22 June 2011
}}</ref> The network is programmed to increase the money supply as a geometric series until the total number of bitcoins reaches 21 million.<ref name="Quantitative Analysis of the Full Bitcoin Transaction Graph"/> {{As of|2012|10}} slightly over 10 million of the total BTC 21 million had been created; the current total number created is available online.<ref>{{cite web
|title= Total Number of Bitcoins in Existence
|url= https://blockexplorer.com/q/totalbc
|work= Bitcoin Block Explorer
|accessdate = 3 October 2012
}}</ref> By 2013 half of the total supply will have been generated, and by 2017, three-quarters will have been generated. To ensure sufficient granularity of the [[money supply]], clients can divide each BTC unit down to eight decimal places (a total of 2.1 × 1015 or 2.1 quadrillion units).<ref name="lwn">{{Cite news
|author= Nathan Willis
|date= 10 November 2010
|title= Bitcoin: Virtual money created by CPU cycles
|publisher= LWN.net
|url= https://lwn.net/Articles/414452/
}}</ref>

The network {{As of|2012|lc=on}} required over one million times more work for confirming a block and receiving an award (BTC 25 {{As of|2012|2|lc=on}}) than when the first blocks were confirmed.
The difficulty is automatically adjusted every 2016 blocks based on the time taken to find the previous 2016 blocks such that one block is created roughly every 10 minutes.

Those who chose to put computational and electrical resources toward mining early on had a greater chance at receiving awards for block generations. This served to make available enough processing power to process blocks. Indeed, without miners there are no transactions and the bitcoin economy comes to a halt.

===Exchange rate===
Prices fluctuate relative to goods and services more than more widely accepted currencies;
the price of a bitcoin is not static.

In August 2012, 1 bitcoin traded at around US$10.00. Taking into account the total number of bitcoins mined, the monetary base of the Bitcoin network stands at over USD 110 million.<ref>[http://www.bitcoinwatch.com/ http://www.bitcoinwatch.com/] Bitcoin statistics</ref>

== Anonymity ==
{{main|Anonymity & Security}}

=== Transactions ===

While using bitcoins is an excellent way to make your purchases, donations, and p2p payments without losing money through inflated transaction fees, transactions are never truly anonymous. Buying bitcoin you pass identification, Bitcoin transactions are stored publicly and permanently on the network, which means anyone can see the balance and transactions of any Bitcoin address. Bitcoin activities are recorded and available publicly via the [[blockchain]], a comprehensive database which keeps a record of Bitcoin transactions.

=== Buying/selling bitcoins ===

All exchange companies require the user to scan ID documents, and large transactions must be reported to the proper governmental authority.

This means that a third party with an interest in tracking your activities can use your visible balance and ID information as a basis from which to track your future transactions or to study previous activity. In short, you have compromised your [[security]] and [[privacy]].

In addition to conventional exchanges there are also peer-to-peer exchanges. Peer to peer exchanges will often not collect KYC and identity information directly from users, instead they let the users handle KYC amongst themselves. These can often be a better alternative for those looking to purchase bitcoins quickly and without KYC delay.

=== Mixing services ===

[http://anonymity.co.in/mixing_services.html Mixing services] are used to avoid compromising of privacy and security. Mixing services provide to periodically exchange your bitcoins for different ones which cannot be associated with the original owner.

== Security ==
{{seealso|Weaknesses}}

In the history of Bitcoin, there have been a few [[incidents]], caused by problematic as well as malicious transactions. In the worst such incident, and the only one of its type, a person was able to pretend that he had a practically infinite supply of bitcoins, for almost 9 hours.

Bitcoin relies, among other things, on [https://en.wikipedia.org/wiki/Public-key_cryptography public key cryptography] and thus may be vulnerable to [https://en.wikipedia.org/wiki/Elliptic_curve_cryptography#Quantum_computing_attacks quantum computing attacks] if and when practical quantum computers can be constructed.

If multiple different software packages, whose usage becomes widespread on the Bitcoin network, disagree on the protocol and the rules for transactions, this could potentially cause a fork in the block chain with each faction of users being able to accept only their own version of the history of transactions. This could influence the price of bitcoins.

A global, organized campaign against the currency or the software could also influence the demand for bitcoins, and thus the exchange price.

==Bitcoin mining==
{{main|Mining}}

Bitcoin mining nodes are responsible for managing the Bitcoin network.

Bitcoins are awarded to Bitcoin nodes known as "miners" for the solution to a difficult [[proof-of-work]] problem which confirms transactions and prevents double-spending. This incentive, as the Nakamoto white paper describes it, encourages "nodes to support the network, and provides a way to initially distribute coins into circulation, since no central authority issues them."<ref name="whitepaper" />

Nakamoto compared the generation of new coins by expending CPU time and electricity to gold miners expending resources to add gold to circulation.<ref name="whitepaper"/>

[[File:Cryptocurrency Mining Farm.jpg|right|350px|thumb|Iceland is a good location for [[mining]] bitcoins because of the natural cold temperature.]]

===Node operation===

The node software for the Bitcoin network is based on peer-to-peer networking, digital signatures and cryptographic proof to make and verify transactions. Nodes broadcast transactions to the network, which records them in a public record of all transactions called the ''blockchain'' after validating them with a [[proof-of-work|proof-of-work system]].

Satoshi Nakamoto designed the first Bitcoin node and mining software<ref name="processors">{{Cite news
|last= Davis
|first= Joshua
|title= The Crypto-Currency
|url= https://www.wired.com/magazine/2011/11/mf_bitcoin/all
|accessdate = 11 November 2011
|newspaper= Wired Magazine
|date= 10 November 2011
}}</ref> and developed the majority of the first implementation, Bitcoind, from 2007 to mid-2010.<ref name="code_start">{{cite web
|url= https://bitcointalk.org/index.php?topic=13.msg46#msg46
|title= Questions about Bitcoin
|publisher= Bitcoin forum
|date= 10 December 2009
}}</ref>

Node implementations include core software such as Bitcoind/Bitcoin-Qt, [[libbitcoin]], [[cbitcoin]]<ref>{{Cite web|title=cbitcoin|url=https://github.com/MatthewLM/cbitcoin|accessdate=3 October 2012}}</ref> and [[BitCoinJ|bitcoinj]].<ref>{{cite web
|url= https://news.slashdot.org/story/11/03/23/0210207/Google-Engineer-Releases-Open-Source-Bitcoin-Client
|title= Google Engineer Releases Open Source Bitcoin Client
|author= angry tapir, timothy
|date= 23 March 2011
|publisher= Slashdot
|accessdate = 18 May 2011
}}</ref><ref>{{cite web
|url= http://www.javaworld.com/javaworld/jw-01-2012/120110-bitcoin-for-beginners-3.html?page=1
|title= Bitcoin for beginners: The BitcoinJ API
|author= Dirk Merkel
|date= 10 January 2012
|publisher= JavaWorld
|accessdate = 3 August 2012
}}</ref>

Every node in the Bitcoin network collects all the unacknowledged transactions it knows of in a file called a ''block'', which also contains a reference to the previous valid block known to that node. It then appends a [[nonce]] value to this previous block and computes the SHA-256 cryptographic hash of the block and the appended nonce value. The node repeats this process until it adds a nonce that allows for the generation of a hash with a value lower than a specified ''target''. Because computers cannot practically reverse the hash function, finding such a nonce is hard and requires on average a predictable amount of repetitious trial and error. This is where the ''[[proof-of-work]]'' concept comes in to play. When a node finds such a solution, it announces it to the rest of the network. Peers receiving the new solved block validate it by computing the hash and checking that it really starts with the given number of zero bits (i.e., that the hash is within the target). Then they accept it and add it to the chain.

===Mining rewards===
In addition to receiving the pending transactions confirmed in the block, a generating node adds a ''generate'' transaction, which awards new bitcoins to the operator of the node that generated the block. The system sets the payout of this generated transaction according to its defined inflation schedule. The miner that generates a block also receives the fees that users have paid as an incentive to give particular transactions priority for faster confirmation.<ref>[https://www.bitcoinmining.com Bitcoin Mining]</ref>

The network never creates more than a BTC 50 reward per block and this amount will decrease over time towards zero, such that no more than BTC 21 million will ever exist.<ref name="lwn" /> As this payout decreases, the incentive for users to run block-generating nodes is intended to change to earning [[#Transaction fees|transaction fees]].

===Mining pools===
{{main|Pooled mining}}

Bitcoin users often pool computational effort to increase the stability of the collected fees and subsidy they receive.<ref name="We Use Coins Mining">{{cite web|title=About Bitcoin Mining|url=https://www.weusecoins.com/en/mining-guide/|publisher=We Use Coins|accessdate=27 May 2015}}</ref>

===Mining difficulty===
{{main|Difficulty}}

In order to throttle the creation of blocks, the difficulty of generating new blocks is adjusted over time. If mining output increases or decreases, the difficulty increases or decreases accordingly.

The adjustment is done by changing the threshold that a hash is required to be less than. A lower threshold means fewer possible hashes can be accepted, and thus a higher degree of difficulty. The target rate of block generation is one block every 10 minutes, or 2016 blocks every two weeks. Bitcoin changes the difficulty of finding a valid block every 2016 blocks, using the difficulty that would have been most likely to cause the prior 2016 blocks to have taken two weeks to generate, according to the timestamps on the blocks. Technically, this is done by modelling the generation of bitcoins as Poisson process. All nodes perform and enforce the same difficulty calculation.

Difficulty is intended as an automatic stabilizer allowing mining for bitcoins to remain profitable in the long run for the most efficient miners, independently of the fluctuations in demand of the bitcoin in relation to other currencies.

===Mining hardware===
{{main|Mining Hardware Comparison}}

Bitcoins used to be mined through Intel/AMD CPUs. {{As of | 2012}}, mining has gradually moved to [[GPU]] and [[FPGA]] hardware.<ref name="bitcoinmag-butterfly" /> [[Application-specific integrated circuit|ASIC]]-based hardware for bitcoin mining has been announced by several manufacturers who intend to ship products from late 2012 to early 2013.<ref name="bitcoinmag-butterfly">{{Cite web|title=Bitpay Breaks Daily Volume Record with Butterfly ASIC mining release|url=http://bitcoinmagazine.net/bitpay-breaks-daily-volume-record-with-butterfly-asic-mining-release/|publisher=Bitcoin Magazine}}</ref>

==Concerns==

===As an investment===
{{main|Bitcoin as an investment}}

Bitcoin describes itself as an experimental digital currency. Reuben Grinberg has noted that Bitcoin's supporters have argued that bitcoins are neither securities nor investments because they fail to meet the criteria for either category.<ref name="grinberg">{{cite web | url=http://papers.ssrn.com/sol3/papers.cfm?abstract_id=1817857 | title=Bitcoin: An Innovative Alternative Digital Currency | publisher=SSRN | date=9 December 2011 | accessdate=4 December 2012 | author=Grinberg, Reuben}}</ref> Although it is a virtual currency, some people see it as an investment<ref name="cnbc">{{cite web | url=http://www.cnbc.com/id/45030812/The_Pros_And_Cons_Of_Biting_on_Bitcoins | title=The Pros And Cons Of Biting on Bitcoins | publisher=CNBC | date=23 November 2011 | accessdate=4 December 2012 | author=Gustke, Constance}}</ref> or accuse it of being a form of investment fraud known as a Ponzi scheme.<ref>{{cite web |url=https://www.theregister.co.uk/2011/06/08/bitcoin_under_attack/ |title=US senators draw a bead on Bitcoin |last1=Chirgwin |first1=Richard |date=8 June 2011 |publisher=The Register |accessdate=14 November 2012}}</ref><ref>{{cite web |url=http://uk.reuters.com/article/2012/04/01/uk-traders-bitcoin-idUKBRE8300JL20120401 |title=Bitcoin, the City traders' anarchic new toy |last1=O'Leary |first1=Naomi |date=2 April 2012 |publisher=Reuters |accessdate=14 November 2012}}</ref> A report by the European Central Bank, using the U.S. Securities and Exchange Commission's definition of a Ponzi scheme, found that the use of bitcoins shares some characteristics with Ponzi schemes, but also has characteristics of its own which contradict several common aspects of Ponzi schemes.<ref name="ecbreport">{{cite web | url=http://www.ecb.europa.eu/pub/pdf/other/virtualcurrencyschemes201210en.pdf | title=Virtual Currency Schemes | publisher=European Central Bank | date=October 2012 | accessdate=4 December 2012}}</ref>

===Privacy===
Because transactions are broadcast to the entire network, they are inherently public. Unlike regular banking,<ref>{{cite web
|url= https://spectrum.ieee.org/computing/software/bitcoin-the-cryptoanarchists-answer-to-cash/0
|title= Bitcoin: The Cryptoanarchists' Answer to Cash
|publisher= IEEE.org
|date= June 2012
|accessdate = 5 June 2012
}}</ref> which preserves customer privacy by keeping transaction records private, loose transactional privacy is accomplished in Bitcoin by using many unique addresses for every wallet while at the same time publishing all transactions. As an example, if Alice sends BTC 123.45 to Bob, the network creates a public record that allows anyone to see that 123.45 has been sent from one address to another. However, unless Alice or Bob make their ownership of these addresses known, it is difficult for anyone else to connect the transaction with them. However, if someone connects an address to a user at any point they could follow back a series of transactions as each participant likely knows who paid them and may disclose that information on request or under duress.

It can be difficult to associate Bitcoin identities with real-life identities.<ref name="An Analysis of Anonymity in the Bitcoin System">Fergal Reid and Martin Harrigan (24 July 2011). [https://anonymity-in-bitcoin.blogspot.com/2011/07/bitcoin-is-not-anonymous.html An Analysis of Anonymity in the Bitcoin System]. An Analysis of Anonymity in the Bitcoin System.</ref> This property makes Bitcoin transactions attractive to sellers of illegal products.<ref name="Forbes">Andy Greenberg (20 April 2011). [http://www.forbes.com/forbes/2011/0509/technology-psilocybin-bitcoins-gavin-andresen-crypto-currency.html Crypto Currency]. Forbes Magazine.</ref><ref>{{cite web
|last= Madrigal
|first= Alexis
|title= Libertarian Dream? A Site Where You Buy Drugs With Digital Dollars
|publisher= The Atlantic Monthly
|date= 1 June 2011
|url= https://www.theatlantic.com/technology/archive/2011/06/libertarian-dream-a-site-where-you-buy-drugs-with-digital-dollars/239776/
|accessdate = 5 June 2011
}}</ref>

===Illicit use===

====Cracking====
The cracking organization "LulzSec" accepted donations in bitcoins, having said that the group "needs Bitcoin donations to continue their hacking efforts".<ref name="CNET">{{cite web
|last= Reisinger
|first= Don
|url= https://news.cnet.com/8301-13506_3-20070268-17/senators-target-bitcoin-currency-citing-drug-sales/
|title= Senators target Bitcoin currency, citing drug sales | The Digital Home – CNET News
|publisher= News.cnet.com
|date= 9 June 2011
|accessdate = 22 June 2011
}}</ref><ref>{{cite news
|last= Olson
|first= Parmy
|url= http://blogs.forbes.com/parmyolson/2011/06/06/lulzsec-hackers-posts-sony-dev-source-code-get-7k-donation/
|title= LulzSec Hackers Post Sony Dev. Source Code, Get $7K Donation – Parmy Olson – Disruptors – Forbes
|publisher= Blogs.forbes.com
|date= 6 June 2011
|accessdate = 22 June 2011
}}</ref>

====Silk Road====
[[Silk Road]] is an anonymous black market that uses only the bitcoin.<ref name="npr-06-12-11">
{{Cite news
|url= https://www.npr.org/2011/06/12/137138008/silk-road-not-your-fathers-amazon-com
|date= 12 June 2011
|newspaper= NPR
|title= Silk Road: Not Your Father's Amazon.com
|author= Staff
}}</ref>

In a 2011 letter to Attorney General Eric Holder and the Drug Enforcement Administration, senators Charles Schumer of New York and Joe Manchin of West Virginia called for an investigation into Silk Road and the bitcoin.<ref name="npr-06-12-11"/>
Schumer described the use of bitcoins at Silk Road as a form of money laundering.<ref name="ars-06-08-11"/>

====Botnet mining====
In June 2011, Symantec warned about the possibility of botnets engaging in covert "mining" of bitcoins,<ref>{{Cite web|author=Updated: 17 June 2011 | Translations available: 日本語 |url=http://www.symantec.com/connect/blogs/bitcoin-botnet-mining |title=Bitcoin Botnet Mining | Symantec Connect Community |publisher=Symantec.com |date=17 June 2011 |accessdate = 24 January 2012}}</ref><ref>{{Cite web|url=http://www.zdnet.com/blog/security/researchers-find-malware-rigged-with-bitcoin-miner/8934 |title=Researchers find malware rigged with Bitcoin miner |publisher=ZDNet |date=29 June 2011 |accessdate = 24 January 2012}}</ref> consuming computing cycles, using extra electricity and possibly increasing the temperature of the computer (not associated with [http://snowafter.com Snow Day Calculator]). Later that month, the Australian Broadcasting Corporation caught an employee using the company's servers to generate bitcoins without permission.<ref>{{Cite web|url=http://thenextweb.com/au/2011/06/23/abc-employee-caught-mining-for-bitcoins-on-company-servers/ |title=ABC employee caught mining for Bitcoins on company servers |publisher=The Next Web |date=23 June 2011 |accessdate = 24 January 2012}}</ref> Some malware also uses the parallel processing capabilities of the GPUs built into many modern-day video cards.<ref>{{Cite news |url=https://www.theregister.co.uk/2011/08/16/gpu_bitcoin_brute_forcing/ |title=Malware mints virtual currency using victim's GPU |date=16 August 2011|first=Dan |last=Goodin }}</ref> In mid August 2011, bitcoin miner botnets were found;<ref>{{Cite web|url=http://www.infosecurity-magazine.com/view/20211/researcher-discovers-distributed-bitcoin-cracking-trojan-malware/ |title=Infosecurity – Researcher discovers distributed bitcoin cracking trojan malware |publisher=Infosecurity-magazine.com |date=19 August 2011 |accessdate = 24 January 2012}}</ref> trojans infecting Mac OS X have also been uncovered.<ref>{{Cite web|url=http://www.techworld.com.au/article/405849/mac_os_x_trojan_steals_processing_power_produce_bitcoins |title=Mac OS X Trojan steals processing power to produce Bitcoins – sophos, security, malware, Intego – Vulnerabilities – Security |publisher=Techworld |date=1 November 2011 |accessdate = 24 January 2012}}</ref>

===Theft and fraud===
On 19 June 2011, a security breach of the Mt.Gox (an acronym for ''M''agic: ''T''he ''G''athering ''O''nline E''x''change, its original purpose) bitcoin exchange caused the price of a bitcoin to briefly drop to US$0.01 on the Mt.Gox exchange (though it remained unaffected on other exchanges) after a hacker allegedly used credentials from a Mt.Gox auditor's compromised computer to illegally transfer a large number of bitcoins to him- or herself and sell them all, creating a massive "ask" order at any price. Within minutes the price rebounded to over $15 before Mt.Gox shut down their exchange and cancelled all trades that happened during the hacking period.<ref>[https://mtgox.com/press_release_20110630.html Clarification of Mt Gox Compromised Accounts and Major Bitcoin Sell-Off]</ref><ref>[https://www.youtube.com/watch?v=T1X6qQt9ONg YouTube. Bitcoin Report]</ref> The exchange rate of bitcoins quickly returned to near pre-crash values.<ref name="mick">Jason Mick, 19 June 2011, [http://www.dailytech.com/Inside+the+MegaHack+of+Bitcoin+the+Full+Story/article21942.htm Inside the Mega-Hack of Bitcoin: the Full Story], DailyTech</ref><ref>Timothy B. Lee, 19 June 2011, [https://arstechnica.com/tech-policy/news/2011/06/bitcoin-price-plummets-on-compromised-exchange.ars Bitcoin prices plummet on hacked exchange], Ars Technica</ref><ref>Mark Karpeles, 20 June 2011, [https://support.mtgox.com/entries/20208066-huge-bitcoin-sell-off-due-to-a-compromised-account-rollback Huge Bitcoin sell off due to a compromised account – rollback], Mt.Gox Support</ref><ref name="register1">{{Cite news
|title= Bitcoin collapses on malicious trade – Mt Gox scrambling to raise the Titanic
|url= https://www.theregister.co.uk/2011/06/19/bitcoin_values_collapse_again/
|date= 19 June 2011
|author= Chirgwin, Richard
|publisher= The Register
}}</ref> Accounts with the equivalent of more than USD 8,750,000 were affected.<ref name="mick" />

In July 2011, The operator of Bitomat, the third largest bitcoin exchange, announced that he lost access to his wallet.dat file with about 17,000 bitcoins (roughly equivalent to USD 220,000 at that time). He announced that he would sell the service for the missing amount, aiming to use funds from the sale to refund his customers.<ref>[http://siliconangle.com/blog/2011/08/01/third-largest-bitcoin-exchange-bitomat-lost-their-wallet-over-17000-bitcoins-missing/ Third Largest Bitcoin Exchange Bitomat Lost Their Wallet, Over 17,000 Bitcoins Missing]. SiliconAngle</ref>

In August 2011, MyBitcoin, one of the popular Bitcoin transaction processors, declared that it was hacked, which resulted in it being shut down with paying 49% on customer deposits leaving more than 78,000 BitCoins (roughly equivalent to USD 800,000 at that time) unaccounted for.<ref>[http://betabeat.com/2011/08/mybitcoin-spokesman-finally-comes-forward-what-did-you-think-we-did-after-the-hack-we-got-shitfaced/ MyBitcoin Spokesman Finally Comes Forward: “What Did You Think We Did After the Hack? We Got Shitfaced”]. BetaBeat</ref><ref>[http://betabeat.com/2011/08/search-for-owners-of-mybitcoin-loses-steam/ Search for Owners of MyBitcoin Loses Steam]. BetaBeat</ref>

In early August 2012, a lawsuit was filed in San Francisco court against Bitcoinica, claiming about USD 460,000 from the company. Bitcoinica was hacked twice in 2012, which led to allegations of neglecting the safety of customers' money and cheating them out of withdrawal requests.<ref>[https://arstechnica.com/tech-policy/2012/08/bitcoinica-users-sue-for-460k-in-lost-bitcoins/ Bitcoinica users sue for $460k in lost Bitcoins]. Arstechnica</ref><ref>[https://spectrum.ieee.org/tech-talk/computing/networks/first-bitcoin-lawsuit-filed-in-san-francisco First Bitcoin Lawsuit Filed In San Francisco]. IEEE Spectrum</ref>

In late August 2012, Bitcoin Savings and Trust was shut down by the owner, allegedly leaving around $5.6 million in debts; this led to allegations of the operation being a Ponzi scheme.<ref>{{Cite web|title=Bitcoin ponzi scheme – investors lose $5 million USD in online hedge fund|url=https://rt.com/usa/news/investors-currency-digital-fund-868/|publisher=RT}}</ref><ref>{{Cite web|last=Jeffries|first=Adrianne|title=Suspected multi-million dollar Bitcoin pyramid scheme shuts down, investors revolt|url=http://www.theverge.com/2012/8/27/3271637/bitcoin-savings-trust-pyramid-scheme-shuts-down|publisher=The Verge}}</ref><ref>{{Cite web|last=Mick|first=Jason|title="Pirateat40" Makes Off $5.6M USD in Bitcoin From Pyramid Scheme|url=http://www.dailytech.com/Pirateat40+Makes+Off+56M+USD+in+BitCoins+From+Pyramid+Scheme/article25538.htm|publisher=DailyTech}}</ref><ref>[https://pandodaily.com/2012/08/31/bitcoin-how-a-virtual-currency-became-real-with-a-5-6m-fraud/ Bitcoin: How a Virtual Currency Became Real with a $5.6M Fraud]. PandoDaily</ref> In September 2012, it was reported that U.S. Securities and Exchange Commission has started an investigation on the case.<ref>[http://blogs.telegraph.co.uk/technology/willardfoxton2/100007836/bitcoin-pirate-scandal-sec-steps-in-amid-allegations-that-the-whole-thing-was-a-ponzi-scheme/ Bitcoin 'Pirate' scandal: SEC steps in amid allegations that the whole thing was a Ponzi scheme ]. The Telegraph</ref>

In September 2012, Bitfloor bitcoin exchange also reported being hacked, with 24,000 bitcoins (roughly equivalent to USD 250,000) stolen. As a result, Bitfloor suspended operations.<ref>[http://www.bbc.co.uk/news/technology-19486695 Bitcoin theft causes Bitfloor exchange to go offline]. BBC</ref><ref>[http://www.theverge.com/2012/9/5/3293375/bitfloor-bitcoin-exchange-suspended-theft Bitcoin exchange BitFloor suspends operations after $250,000 theft bitcoin exchange BitFloor suspends operations after $250,000 theft]. The Verge</ref> The same month, Bitfloor resumed operations, with its founder saying that he reported the theft to FBI, and that he is planning to repay the victims, though the time frame for such repayment is unclear.<ref>[http://www.pcworld.com/article/2010586/bitcoin-exchange-back-online-after-hack.html?tk=rel_news Bitcoin exchange back online after hack]. PCWorld</ref>

===Taxation===
In September 2012, the Intra-European Organization of Tax Administrations (IOTA), in Tbilisi, Georgia, held a workshop titled "Auditing Individuals and Legal Entities in the Use of e-Money". The workshop was attended by representatives from 23 countries.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Jerry Taylor, IOTA's technical taxation expert, said, "There's an awful lot happening on the Internet environment which is fascinating at the moment and introducing new challenges for auditors when it comes to virtual currency."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Bitcoin was mentioned during the workshop.<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

Matthew Elias, founder of the [[Cryptocurrency Legal Advocacy Group]] (CLAG) published "Staying Between the Lines: A Survey of U.S. Income Taxation and its Ramifications on Cryptocurrencies", which discusses "the taxability of cryptocurrencies such as Bitcoin".<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> CLAG "stressed the importance for taxpayers to determine on their own whether taxes are due on a Bitcoin-related transaction based on whether one has "experienced a realization event."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Such examples are "when a taxpayer has provided a service in exchange for Bitcoins, a realization event has probably occurred, and any gain or loss would likely be calculated using fair market values for the service provided."<ref name="Bitcoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

[[Peter Vessenes]], [[Bitcoin Foundation|Bitcoin Foundation's]] executive director, said, since the foundation is trying to pay for everything in bitcoins, including salaries, "How do we W-2 someone for their Bitcoins? Do we mark-to-market every time a transfer happens? Payroll companies cringe."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> The Bitcoin Foundation hopes "to push for solid guidance about its legal and tax treatment." [[Patrick Murck]], legal counsel for the Bitcoin Foundation, said he would like "to help regulators understand the technology better so they can make better decisions."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref> Murck said, "Bitcoin has the potential to become much more than a niche currency, but it needs the guidance and understanding of regulators." and "The full potential of Bitcoin could be realized through clearer guidelines and a better understanding by financial and tax regulators." and "Part of making that happen is to talk to regulators, the IRS, and tax professionals and helping them understand that Bitcoin is not this nefarious thing, it's just software, it's a community, and there's nothing inherently nefarious about either of those things."<ref name="BitCoin Tax issues Oct 2012">{{cite journal | title=2012 TNT 209-4 NEWS ANALYSIS: VIRTUAL CURRENCY: A NEW WORRY FOR TAX ADMINISTRATORS? (Release Date: OCTOBER 17, 2012) (Doc 2012-21516) | author=Stewart, David D. and Soong Johnston, Stephanie D. | journal=Tax Notes Today | date=29 October 2012 | volume=2012 TNT 209-4 | issue=2012 TNT 209-4}}</ref>

==See Also==
* [[Introduction]]
* [[Getting started]]
* [[Using_Bitcoin|Detailed tutorial]]
* [[FAQ]]
* [https://www.weusecoins.com What Is Bitcoin?]
* [https://www.bitcoinmining.com What Is Bitcoin Mining?]

==Where to check Bitcoin price==
[https://www.coingecko.com/en/coins/bitcoin Coingecko BTC price]
 
[https://coinriders.com/coin/bitcoin Coinriders BTC price]
 
[https://www.livecoinwatch.com/price/Bitcoin-BTC Livecoinwatch BTC price]

==Where to find Bitcoin Atm near me==

[https://paxful.com/atm Paxful]
 
[https://coinatmradar.com/ coinatmradar.]

==References==
<references />

[[Category:Digital currencies]]
{{wp}}{{p-move}}{{good}}
[[es:Bitcoin]][[de:Bitcoin]]

User talk:Venkatworks

2025-12-19T13:42:55Z

NotATether: /* Rejected edit */ new section

== Rejected edit ==

Your edit for the [[Bitcoin]] page with the content below has been rejected:

<pre>
- * [https://[removed by spam filter]/cryptocurrency-exchange-software-development Crypto Exchange]

+ * [https://www.coinexra.com/white-label-crypto-exchange Crypto Exchange]
</pre>

Reason: Please avoid promoting commercial websites on the Bitcoin page. Create a new page for the website if you want to write about it.

--[[User:NotATether|NotATether]] ([[User talk:NotATether|talk]]) 13:42, 19 December 2025 (UTC)

Secp256k1

2025-12-14T15:17:22Z

NotATether: add graph of sampled points

[[File:Secp256k1.png|thumb |This is a graph of secp256k1's elliptic curve ''y2 = x3 + 7'' over the real numbers. Note that because secp256k1 is actually defined over the field Zp, its graph will in reality look like random scattered points, not anything like this.]]

'''secp256k1''' refers to the parameters of the elliptic curve used in Bitcoin's public-key cryptography, and is defined in ''Standards for Efficient Cryptography (SEC)'' (Certicom Research, http://www.secg.org/sec2-v2.pdf). Currently Bitcoin uses secp256k1 with the [[ECDSA]] algorithm, though the same curve with the same public/private keys can be used in some other algorithms such as [[Schnorr]].

secp256k1 was almost never used before Bitcoin became popular, but it is now gaining in popularity due to its several nice properties. Most commonly-used curves have a random structure, but secp256k1 was constructed in a special non-random way which allows for especially efficient computation. As a result, it is often more than 30% faster than other curves if the implementation is sufficiently optimized. Also, unlike the popular NIST curves, secp256k1's constants were selected in a predictable way, which significantly reduces the possibility that the curve's creator inserted any sort of backdoor into the curve.

=== Technical details ===

[[File:Secp256k1-many.png|thumb |A sample of many points from a graph of a smaller elliptic curve similar to secp256k1. Image by [https://bitcoin.stackexchange.com/a/21911 Pieter Wuille].]]

As excerpted from ''Standards'':

The elliptic curve domain parameters over F''p'' associated with a Koblitz curve secp256k1 are specified
by the sextuple T = (''p,a,b,G,n,h'') where the finite field F''p'' is defined by:
* ''p'' = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F
* = 2256 - 232 - 29 - 28 - 27 - 26 - 24 - 1

The curve ''E'': ''y2 = x3+ax+b'' over F''p'' is defined by:
* ''a'' = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
* ''b'' = 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000007

The base point G in compressed form is:
* ''G'' = 02 79BE667E F9DCBBAC 55A06295 CE870B07 029BFCDB 2DCE28D9 59F2815B 16F81798
and in uncompressed form is:
* ''G'' = 04 79BE667E F9DCBBAC 55A06295 CE870B07 029BFCDB 2DCE28D9 59F2815B 16F81798 483ADA77 26A3C465 5DA4FBFC 0E1108A8 FD17B448 A6855419 9C47D08F FB10D4B8
Finally the order ''n'' of ''G'' and the cofactor are:
* ''n'' = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364141
* ''h'' = 01

=== Properties ===

* secp256k1 has characteristic ''p'', it is defined over the prime field ℤ''p''. Some other curves in common use have characteristic ''2'', and are defined over a binary Galois field ''GF(2n)'', but secp256k1 is not one of them.
* As the ''a'' constant is zero, the ''ax'' term in the curve equation is always zero, hence the curve equation becomes ''y2 = x3 + 7''.

== See also ==

* [https://bitcoin.stackexchange.com/questions/21907/what-does-the-curve-used-in-bitcoin-secp256k1-look-like What does secp256k1 look like] (Bitcoin stack exchange answer by Pieter Wuille)

[[es:Secp256k1]]

[[Category:Technical]]

File:Secp256k1-many.png

2025-12-14T15:13:46Z

NotATether: A graph of the secp256k1 curve across many points.

== Summary ==
A graph of the secp256k1 curve across many points.

/r/Bitcoin

2025-12-14T13:16:19Z

NotATether: update stats

{{infobox company
|foundation=September 9th, 2010
|subreddit=Bitcoin
}}'''/r/Bitcoin''' is a community on the popular social sharing website [http://www.reddit.com/r/bitcoin Reddit]. This community was founded [http://redditmetrics.com/r/Bitcoin September 9th, 2010] by Atlas, and has become one of the largest bitcoin communities for news, community feedback, and up to date information about companies and relevant activities to all things Bitcoin.

The community has grown substantially, particularly after the 2013 October hack of Bitcointalk. As of December 2025, the community has over 8M members, constantly having more than two thousand online and often has hundreds of users browsing the threads at any given moment during the day.

Some notable events covered on /r/bitcoin include [https://www.reddit.com/r/Bitcoin/comments/2hj2lc/the_secret_goldman_sachs_tapes_the_reporter_jake/ The Goldman Sachs Secret Tapes] [https://www.reddit.com/r/Bitcoin/comments/2nab2a/western_union_filed_a_copyright_claim_against_me/ The Western Union Copyright Suit over Parody] [https://www.reddit.com/r/Bitcoin/comments/3fe92x/im_ashley_barr_aka_adam_turner_the_first_mtgox/ Mt. Gox Ex. Employee AMA in Aug. 2015] and the direct message from Wikipedia founder, [https://www.reddit.com/r/Bitcoin/comments/201fa6/hello_from_jimmy_wales_of_wikipedia/ Jimmy Wales].

{{stub}}
[[Category:Properties established in 2010]]
[[Category:Forums]]

BlockChain.info

2025-12-14T13:08:59Z

NotATether: Adjust redirect

#REDIRECT [[Blockchain.com]]

Blockchain.info

2025-12-14T13:08:28Z

NotATether: redirect Blockchain.info to Blockchain.com

#REDIRECT [[Blockchain.com]]

Blockchain.com

2025-12-14T13:07:26Z

NotATether: Create Blockchain.com page as per best practices

{{Infobox company
| name = Blockchain.com
| image = [[File:Blockchain.com logo.png|150px]]
| industry = [[Cryptocurrency]]
| founder = Peter Smith Nicolas Cary Ben Reeves
| website = [https://www.blockchain.com blockchain.com]
}}

'''Blockchain.com''' (formerly '''Blockchain.info''') is a cryptocurrency financial services company. The company provides [[wallet]] services, a crypto [[exchange]], a [[block explorer]], and institutional services including trading and lending.

Founded in August 2011 in York, England, it originally launched as the first widely used Bitcoin block explorer.<ref name="about">{{cite web |url=https://www.blockchain.com/about |title=About Us |publisher=Blockchain.com |access-date=2025-12-14}}</ref> As of 2025, Blockchain.com reports over 94 million wallets created, more than 39 million verified users, and over $1 trillion in cumulative transaction volume.<ref name="crunchbase">{{cite web |url=https://www.crunchbase.com/organization/blockchain-info |title=Blockchain.com - Crunchbase Company Profile |publisher=Crunchbase |access-date=2025-12-14}}</ref>

== History ==
Blockchain.com was founded in August 2011 by Peter Smith, Nicolas Cary, and Ben Reeves in York, England.<ref name="wikipedia">{{cite web |url=https://en.wikipedia.org/wiki/Blockchain.com |title=Blockchain.com |publisher=Wikipedia |access-date=2025-12-14}}</ref> Early investor [[Roger Ver]] provided initial funding.

Initially operating as Blockchain.info, the platform focused on providing a Bitcoin blockchain explorer. In 2013, it introduced a popular non-custodial cryptocurrency wallet.

The company re-branded to Blockchain.com in 2018 and launched its cryptocurrency exchange in 2019, expanding to support buying, selling, trading, and institutional services across numerous cryptocurrencies.

The headquarters later moved to Luxembourg.

== References ==

File:Blockchain.com logo.png

2025-12-14T12:45:28Z

NotATether:

Unciphered

2025-12-14T12:02:56Z

NotATether: remove non-existing categories

'''Unciphered''' is a cryptocurrency recovery company specializing in recovering access to locked or inaccessible hardware and software wallets, corrupted files, and complex crypto access scenarios using advanced cryptographic and hardware forensic techniques.<ref>https://www.unciphered.com/about/</ref>

== History ==
Unciphered was founded in 2021 by Eric Michaud and other veterans from the information security, cryptography, and blockchain fields.<ref>https://www.crunchbase.com/organization/unciphered</ref> Michaud, after recovering over $10 million in cryptocurrency at an unnamed prior company, identified a need for more sophisticated recovery methods beyond brute-force approaches.<ref>https://www.linkedin.com/company/unciphered</ref>

== Services ==
Unciphered provides institutional-grade recovery services for locked cryptocurrency wallets, including hardware devices and software wallets.<ref>https://www.unciphered.com/about/</ref> Services include:
* Password breaking using proprietary tools and individualized models
* Exploit development for hardware and software vulnerabilities
* Data forensics for recovering assets from damaged devices or complex scenarios
* Blockchain analysis and cryptographic research
The company operates a dedicated hardware forensics lab and ensures assets are returned quickly without prolonged custody.

== Notable activities ==

* Disclosed the "Randstorm" vulnerability in 2023, affecting Bitcoin wallets generated with BitcoinJS and certain browser libraries between 2011 and 2015 due to weak randomness.<ref>https://www.unciphered.com/disclosure-of-vulnerable-bitcoin-wallet-library-2/</ref>
* Demonstrated physical extraction and vulnerabilities in hardware wallets, including OneKey and Trezor models.<ref>https://www.coindesk.com/tech/2023/05/24/crypto-security-firm-unciphered-claims-ability-to-physically-hack-trezor-t-wallet</ref>
* Developed a technique to crack IronKey encrypted USB drives, publicly offering in 2023 to recover 7,002 BTC (worth hundreds of millions) for Stefan Thomas, though the offer was declined.<ref>https://www.wired.com/story/unciphered-ironkey-password-cracking-bitcoin/</ref>

== External links ==
* [https://www.unciphered.com/ Official website]

== References ==
<references/>

{{stub}}

[[Category:Cryptocurrency companies]]

Unciphered

2025-12-14T12:01:55Z

NotATether: Emphasize that the previous company is unknown

Unciphered

2025-12-14T11:58:55Z

NotATether: Create Unciphered page

'''Unciphered''' is a cryptocurrency recovery company specializing in recovering access to locked or inaccessible hardware and software wallets, corrupted files, and complex crypto access scenarios using advanced cryptographic and hardware forensic techniques.<ref>https://www.unciphered.com/about/</ref>

== History ==
Unciphered was founded in 2021 by Eric Michaud and other veterans from the information security, cryptography, and blockchain fields.<ref>https://www.crunchbase.com/organization/unciphered</ref> Michaud, after recovering over $10 million in cryptocurrency at a prior company, identified a need for more sophisticated recovery methods beyond brute-force approaches.<ref>https://www.linkedin.com/company/unciphered</ref>

== Services ==
Unciphered provides institutional-grade recovery services for locked cryptocurrency wallets, including hardware devices and software wallets.<ref>https://www.unciphered.com/about/</ref> Services include:
* Password breaking using proprietary tools and individualized models
* Exploit development for hardware and software vulnerabilities
* Data forensics for recovering assets from damaged devices or complex scenarios
* Blockchain analysis and cryptographic research
The company operates a dedicated hardware forensics lab and ensures assets are returned quickly without prolonged custody.

== Notable activities ==

* Disclosed the "Randstorm" vulnerability in 2023, affecting Bitcoin wallets generated with BitcoinJS and certain browser libraries between 2011 and 2015 due to weak randomness.<ref>https://www.unciphered.com/disclosure-of-vulnerable-bitcoin-wallet-library-2/</ref>
* Demonstrated physical extraction and vulnerabilities in hardware wallets, including OneKey and Trezor models.<ref>https://www.coindesk.com/tech/2023/05/24/crypto-security-firm-unciphered-claims-ability-to-physically-hack-trezor-t-wallet</ref>
* Developed a technique to crack IronKey encrypted USB drives, publicly offering in 2023 to recover 7,002 BTC (worth hundreds of millions) for Stefan Thomas, though the offer was declined.<ref>https://www.wired.com/story/unciphered-ironkey-password-cracking-bitcoin/</ref>

== External links ==
* [https://www.unciphered.com/ Official website]

== References ==
<references/>

{{stub}}

[[Category:Cryptocurrency companies]]
[[Category:Companies established in 2021]]
[[Category:Wallet recovery services]]

Javascript cryptography

2025-12-14T11:12:36Z

NotATether: Add Randstorm reference

'''Javascript cryptography''' is when cryptographic software, especially [[bitcoin]] software, is written in javascript.

Javascript is not a suitable language for this. Such software is best avoided.

== Explanation ==

Please don't use any javascript address generator for anything that matters.

The common libraries they have used have had a long and worrying series of mathematical flaws that cause them to occasionally generate addresses that do not match the private keys, and were completely without the sorts of test that would have detected these mistakes. Even if the errors are all fixed now, it's very easy for a webpage generator to be using an old version without anyone really noticing.

This is even before you get into the fact of how easy it is for sites to quietly substitute different JS, or the fact that HTTPS provides virtually no protection against attackers with a network position close to the server (because you can get a cert for any domain you can answer HTTP requests for...). <ref>https://www.reddit.com/r/Bitcoin/comments/6ss91w/seriously_how_are_you_all_generating_your_private/dlf4uhr/</ref>

Generally the code out there uses almost completely untested ECC code which would sometimes generate the wrong pubkeys, as well as being insecure non-constant time implementation subject to surveillance from other javascript tabs.

A major example is the "Randstorm" vulnerability disclosed by Unciphered, affecting JavaScript-based Bitcoin wallets generated using the BitcoinJS library (and derivatives) between 2011 and 2015.<ref>https://www.unciphered.com/disclosure-of-vulnerable-bitcoin-wallet-library-2/</ref> Due to flaws in the SecureRandom() function from the underlying JSBN library, combined with weak browser implementations of Math.random(), private keys were often generated with far less entropy than required (sometimes under 48 bits instead of 256), making them highly predictable and vulnerable to brute-force attacks. It is recommended that anyone using vulnerable software should transfer their bitcoins to a new wallet.

== SF Bitcoin Devs Seminar talk==

Greg Maxwell discusses javascript cryptography. (watch time: 3 min 6 sec)

https://www.youtube.com/watch?v=TYQ-3VvNCHE&t=3071

== See Also ==
* [[Paper wallet]]
* [[Browser-based wallet]]

==References==
<references />

[[Category:Technical]]

Talk:Running Bitcoin

2025-12-14T11:03:46Z

NotATether: Merge with Bitcoin Core?

== Merge topic? ==

I propose merging this topic with [[Bitcoin Core]] as this page is functionally a subset of it.

Technically I don't think there is anything blocking this merge

--[[User:NotATether|NotATether]] ([[User talk:NotATether|talk]]) 11:03, 14 December 2025 (UTC)

Full node

2025-12-14T10:57:13Z

NotATether: Update sizes

Any computer that connects to the Bitcoin [[network]] is called a '''node'''. Nodes that fully verify all of the rules of Bitcoin are called '''full nodes'''. The most popular software implementation of full nodes is called [[Bitcoin Core]], its latest release can be found [https://github.com/bitcoin/bitcoin/releases on the github page]. Another less popular software implementation of full nodes is called [[Bitcoin Knots]], its latest release can be found [https://github.com/bitcoinknots/bitcoin/releases on the github page].

[[File:BitcoinCore-node.jpg|thumb|upright=1|The main window of Bitcoin Core]]

==What makes a full node?==

Full nodes download every block and transaction and check them against Bitcoin's consensus rules. Here are examples of consensus rules, though there are many more:
* Blocks may only [[controlled supply|create]] a certain number of bitcoins. (Currently 3.125 BTC per block.)
* Transactions must have correct signatures for the bitcoins being spent.
* Transactions/blocks must be in the correct data format.
* Within a single [[block chain]], a transaction output cannot be double-spent.

If a transaction or block violates the consensus rules, then it is absolutely rejected, even if every other node on the network thinks that it is valid. This is one of the most important characteristics of full nodes: they do what's right ''no matter what''. For full nodes, miners actually have fairly limited power: they can only reorder or remove transactions, and only by spending a lot of computing power. A powerful miner is able to execute [[Weaknesses#Attacker_has_a_lot_of_computing_power|some serious attacks]], but because full nodes rely on miners only for a few things, miners could not completely change or destroy Bitcoin.

Nodes that have different ''consensus'' rules are actually using two different networks/currencies. Changing any of the consensus rules requires a [[hard fork]], which can be thought of as creating a new currency and having everyone move to it. Consensus rules are different from ''policy'' rules, which specify how a node or miner prioritizes or discourages certain things. Policy rules can be changed freely, and different nodes can have different policy rules. Because all full nodes must use ''exactly'' the same consensus rules in order to remain compatible with each other, even duplicating bugs and oddities in the original consensus rules, creating a full node from scratch is extremely difficult and dangerous. It is therefore recommended that everyone who wishes to run a full node uses software based on the [[reference client]], which is the only client guaranteed to behave correctly.

At minimum, a full node must download every transaction that has ever taken place, all new transactions, and all block headers. Additionally, full nodes must store information about every unspent transaction output until it is spent. By default full nodes are inefficient in that they download each new transaction at least twice, and they store the entire block chain (more than 600 GB as of 2025) forever, even though only the unspent transaction outputs (<15 GB) are required. Performance can improved by enabling <code>[https://bitcointalk.org/index.php?topic=1377345.0 -blocksonly]</code> mode and enabling [https://bitcoin.org/en/release/v0.12.0#wallet-pruning pruning], and by using faster storage devices such as SSDs.

===Archival Nodes===

A subset of full nodes also accept incoming connections and upload old blocks to other peers on the network. This happens if the software is run with <code>-listen=1</code> as is default. Contrary to some popular misconceptions, being an archival node is not necessary to being a full node. If a user's bandwidth is constrained then they can use <code>-listen=0</code>, if their disk space is constrained they can use pruning, all the while still being a fully-validating node that enforces bitcoin's consensus rules and contributing to bitcoin's overall security.

== Why should you use a full node wallet ==

==== Summary ====
Running a full node is the only way you can use Bitcoin in a trustless way. You will know for sure that all the rules of Bitcoin are being followed, for example that no bitcoins are spent not belonging to the owner, that no coins were spent twice, that no inflation happens outside of the [[Controlled_supply|schedule]] and that all the rules needed to make the system work (e.g. [[difficulty]]) are followed. Full nodes are currently the most [[Privacy|private]] way to use Bitcoin, with nobody else learning which bitcoin [[Address|addresses]] belong to you. Full nodes are the most secure way to use Bitcoin, they do not suffer from many attacks that affect lightweight wallets.

=== Economic strength ===

This is by far the most important reason for running a full node, though it is a little difficult to understand.

As explained previously, full nodes enforce the consensus rules no matter what. However, lightweight nodes do not do this. Lightweight nodes do whatever the majority of mining power says. Therefore, if most of the miners got together to increase their block reward, for example, lightweight nodes would blindly go along with it. If this ever happened, the network would split such that lightweight nodes and full nodes would end up on separate networks, using separate currencies. People using lightweight nodes would be unable to transact with people using full nodes. If all businesses and many users are using full nodes, then this network split is not a ''critical'' problem because users of lightweight clients will quickly notice that they can't send or receive bitcoins to/from most of the people who they usually do business with, and so they'll stop using Bitcoin until the evil miners are overcome, which is the appropriate response. ''However'', if almost everyone on the network is using lightweight nodes in this situation, then everyone would continue being able to transact with each other, and so Bitcoin could very well end up "hijacked" by evil miners.

In practice, miners are unlikely to attempt anything like the above scenario as long as full nodes are prevalent because the miners would lose a lot of money. But the incentives completely change if everyone uses lightweight nodes. In that case, miners definitely ''do'' have an incentive to change Bitcoin's rules in their favor. It is only reasonably secure to use a lightweight node ''because'' most of the Bitcoin economy uses full nodes.

Therefore, it is critical for Bitcoin's survival that the great majority of the Bitcoin economy be backed by full nodes, not lightweight nodes. This is especially important for Bitcoin businesses, which have more economic weight. To contribute to Bitcoin's economic strength, you must actually use a full node for your real transactions (or use a lightweight node connected to a full node that you personally control). Just running a full node on a server somewhere does not contribute to Bitcoin's economic strength.

More details https://www.reddit.com/r/BitcoinBeginners/comments/3eq3y7/full_node_question/ctk4lnd

=== Privacy ===

Downloading the entire blockchain is the most private way to operate a wallet. All other lightweight solutions leak information about which addresses are yours because they must query third-party servers. The Electrum servers will know which addresses belong to you and can link them together. Despite bloom filtering, SPV nodes based on BitcoinJ [[BIP37 privacy problems|do not provide much privacy]] against nodes who connected directly to the wallet.<ref>[https://jonasnick.github.io/blog/2015/02/12/privacy-in-bitcoinj/ Privacy in BitcoinJ ]</ref>

For some use cases, such privacy may not be required. But an important reason to run a full node and use it as a wallet is to get the full privacy benefits.

=== Security ===

Lightweight nodes are sometimes able to be temporarily tricked into accepting transactions or blocks that are not actually valid. This could cause serious financial damage, especially for websites that automatically process Bitcoin transactions. Full nodes provide the maximum security possible, and so they should be used by all businesses, and also by regular users whenever doing so is convenient.

=== Network services ===

Full nodes may provide various services to other network participants (if the software is run with <code>-listen=1</code> as is default). This is especially important for lightweight nodes.

These services include:
* Filtering transactions and blocks on behalf of lightweight nodes so that lightweight nodes do not need to download every transaction ever made on the network in order to find their own transactions.
* Serving historical full blocks to nodes that have been offline for a while.
* Transmitting new transactions from users to miners.
* Broadcasting new blocks from miners to other nodes.

For the most part, these services are only usefully performed by full nodes that are listening on port 8333. The more full nodes that accept incoming connections there are, the more users the Bitcoin network can support. Although if there is ever a shortage, lots of archival nodes can be easily created by cheaply renting VPS or AWS space.

=== Some are incentivizing it ===
Bitnodes ran a program to incentivize full node operators until the end of 2015.<ref>[https://bitcoinmagazine.com/19620/bitnodes-project-issues-first-incentives-node-operators/ Bitnodes Project Issues First Incentives For Node Operators by Joel Dalas] of [http://bitcoinmagazine.com/ Bitcoin Magazine]; cf. https://blog.bitcoinfoundation.org/bitnodes-project-2015-q1-report-peer-index-and-incentivized-full-nodes/</ref>

== How to run a full node ==

If you run the [[Bitcoin Core]]/[[bitcoind]] wallet, you are running a full node. If you open port 8333, you will contribute to the network's capacity. If you actually use the wallet feature, or if you use a lightweight client like [[MultiBit]] but configure it to connect exclusively to your full node, then you will contribute to the network's economic strength and receive protection from some possible attacks against lightweight nodes.

There are a few alternate full node implementations, but they are not recommended for serious use because it is currently difficult to determine whether they implement the consensus rules with 100% accuracy. Even very slight inaccuracies could cause serious problems for the users of these alternate clients. Example of implementations [[libbitcoin]], [[btcd]], [https://bitcoinfo.org/bitcoin-information/full-node.html a list of other Full Nodes].

=== Tips and tricks for running a node ===

For [[Bitcoin Core]]:

* Bandwidth consumption can be reduced using this guide: https://btcinformation.org/en/full-node#reduce-traffic

* Requirement for disk space can be reduced using this guide: https://btcinformation.org/en/full-node#reduce-storage See also the [https://github.com/bitcoin/bitcoin/blob/v0.11.0/doc/release-notes.md#block-file-pruning release notes which explain pruning].

* This site has a nice predefined template for generating bitcoin config files https://jlopp.github.io/bitcoin-core-config-generator/

* Improve sync speed by increasing the dbcache value in configuration. This value controls how many megabytes of RAM to use for the database cache, increase it to as much as your hardware allows to reduce the disk operations and increase speed.

* To store the blockchain files on an external hard drive use <tt>-datadir</tt>. e.g. <tt>-datadir=/path/to/your/bitcoin/directory</tt>.

* Store the chainstate directory on an SSD drive to improve the speed.<ref>[https://www.reddit.com/r/Bitcoin/comments/7iaa3t/if_you_run_a_full_node_on_a_hdd_put_your/ If you run a full node on a hdd put your chainstate directory on an external ssd].</ref>
** See [[Splitting the data directory]]

See Also: [[Running Bitcoin]]

== See Also ==

* [[Clearing Up Misconceptions About Full Nodes]]

* [[Why Your Business Should Use a Full Node to Accept Bitcoin]]

* [[Bitcoin is not ruled by miners]]

==References==
<references />

[[Category:Technical]]
[[Category:Privacy]]

{{Bitcoin Core documentation}}

Full node

2025-12-14T10:51:03Z

NotATether: Add image of Bitcoin Core

Any computer that connects to the Bitcoin [[network]] is called a '''node'''. Nodes that fully verify all of the rules of Bitcoin are called '''full nodes'''. The most popular software implementation of full nodes is called [[Bitcoin Core]], its latest release can be found [https://github.com/bitcoin/bitcoin/releases on the github page]. Another less popular software implementation of full nodes is called [[Bitcoin Knots]], its latest release can be found [https://github.com/bitcoinknots/bitcoin/releases on the github page].

[[File:BitcoinCore-node.jpg|thumb|upright=1|The main window of Bitcoin Core]]

==What makes a full node?==

Full nodes download every block and transaction and check them against Bitcoin's consensus rules. Here are examples of consensus rules, though there are many more:
* Blocks may only [[controlled supply|create]] a certain number of bitcoins. (Currently 3.125 BTC per block.)
* Transactions must have correct signatures for the bitcoins being spent.
* Transactions/blocks must be in the correct data format.
* Within a single [[block chain]], a transaction output cannot be double-spent.

If a transaction or block violates the consensus rules, then it is absolutely rejected, even if every other node on the network thinks that it is valid. This is one of the most important characteristics of full nodes: they do what's right ''no matter what''. For full nodes, miners actually have fairly limited power: they can only reorder or remove transactions, and only by spending a lot of computing power. A powerful miner is able to execute [[Weaknesses#Attacker_has_a_lot_of_computing_power|some serious attacks]], but because full nodes rely on miners only for a few things, miners could not completely change or destroy Bitcoin.

Nodes that have different ''consensus'' rules are actually using two different networks/currencies. Changing any of the consensus rules requires a [[hard fork]], which can be thought of as creating a new currency and having everyone move to it. Consensus rules are different from ''policy'' rules, which specify how a node or miner prioritizes or discourages certain things. Policy rules can be changed freely, and different nodes can have different policy rules. Because all full nodes must use ''exactly'' the same consensus rules in order to remain compatible with each other, even duplicating bugs and oddities in the original consensus rules, creating a full node from scratch is extremely difficult and dangerous. It is therefore recommended that everyone who wishes to run a full node uses software based on the [[reference client]], which is the only client guaranteed to behave correctly.

At minimum, a full node must download every transaction that has ever taken place, all new transactions, and all block headers. Additionally, full nodes must store information about every unspent transaction output until it is spent. By default full nodes are inefficient in that they download each new transaction at least twice, and they store the entire block chain (more than 165 GB as of 20180214) forever, even though only the unspent transaction outputs (<2 GB) are required. Performance can improved by enabling <code>[https://bitcointalk.org/index.php?topic=1377345.0 -blocksonly]</code> mode and enabling [https://bitcoin.org/en/release/v0.12.0#wallet-pruning pruning].

===Archival Nodes===

A subset of full nodes also accept incoming connections and upload old blocks to other peers on the network. This happens if the software is run with <code>-listen=1</code> as is default. Contrary to some popular misconceptions, being an archival node is not necessary to being a full node. If a user's bandwidth is constrained then they can use <code>-listen=0</code>, if their disk space is constrained they can use pruning, all the while still being a fully-validating node that enforces bitcoin's consensus rules and contributing to bitcoin's overall security.

== Why should you use a full node wallet ==

==== Summary ====
Running a full node is the only way you can use Bitcoin in a trustless way. You will know for sure that all the rules of Bitcoin are being followed, for example that no bitcoins are spent not belonging to the owner, that no coins were spent twice, that no inflation happens outside of the [[Controlled_supply|schedule]] and that all the rules needed to make the system work (e.g. [[difficulty]]) are followed. Full nodes are currently the most [[Privacy|private]] way to use Bitcoin, with nobody else learning which bitcoin [[Address|addresses]] belong to you. Full nodes are the most secure way to use Bitcoin, they do not suffer from many attacks that affect lightweight wallets.

=== Economic strength ===

This is by far the most important reason for running a full node, though it is a little difficult to understand.

As explained previously, full nodes enforce the consensus rules no matter what. However, lightweight nodes do not do this. Lightweight nodes do whatever the majority of mining power says. Therefore, if most of the miners got together to increase their block reward, for example, lightweight nodes would blindly go along with it. If this ever happened, the network would split such that lightweight nodes and full nodes would end up on separate networks, using separate currencies. People using lightweight nodes would be unable to transact with people using full nodes. If all businesses and many users are using full nodes, then this network split is not a ''critical'' problem because users of lightweight clients will quickly notice that they can't send or receive bitcoins to/from most of the people who they usually do business with, and so they'll stop using Bitcoin until the evil miners are overcome, which is the appropriate response. ''However'', if almost everyone on the network is using lightweight nodes in this situation, then everyone would continue being able to transact with each other, and so Bitcoin could very well end up "hijacked" by evil miners.

In practice, miners are unlikely to attempt anything like the above scenario as long as full nodes are prevalent because the miners would lose a lot of money. But the incentives completely change if everyone uses lightweight nodes. In that case, miners definitely ''do'' have an incentive to change Bitcoin's rules in their favor. It is only reasonably secure to use a lightweight node ''because'' most of the Bitcoin economy uses full nodes.

Therefore, it is critical for Bitcoin's survival that the great majority of the Bitcoin economy be backed by full nodes, not lightweight nodes. This is especially important for Bitcoin businesses, which have more economic weight. To contribute to Bitcoin's economic strength, you must actually use a full node for your real transactions (or use a lightweight node connected to a full node that you personally control). Just running a full node on a server somewhere does not contribute to Bitcoin's economic strength.

More details https://www.reddit.com/r/BitcoinBeginners/comments/3eq3y7/full_node_question/ctk4lnd

=== Privacy ===

Downloading the entire blockchain is the most private way to operate a wallet. All other lightweight solutions leak information about which addresses are yours because they must query third-party servers. The Electrum servers will know which addresses belong to you and can link them together. Despite bloom filtering, SPV nodes based on BitcoinJ [[BIP37 privacy problems|do not provide much privacy]] against nodes who connected directly to the wallet.<ref>[https://jonasnick.github.io/blog/2015/02/12/privacy-in-bitcoinj/ Privacy in BitcoinJ ]</ref>

For some use cases, such privacy may not be required. But an important reason to run a full node and use it as a wallet is to get the full privacy benefits.

=== Security ===

Lightweight nodes are sometimes able to be temporarily tricked into accepting transactions or blocks that are not actually valid. This could cause serious financial damage, especially for websites that automatically process Bitcoin transactions. Full nodes provide the maximum security possible, and so they should be used by all businesses, and also by regular users whenever doing so is convenient.

=== Network services ===

Full nodes may provide various services to other network participants (if the software is run with <code>-listen=1</code> as is default). This is especially important for lightweight nodes.

These services include:
* Filtering transactions and blocks on behalf of lightweight nodes so that lightweight nodes do not need to download every transaction ever made on the network in order to find their own transactions.
* Serving historical full blocks to nodes that have been offline for a while.
* Transmitting new transactions from users to miners.
* Broadcasting new blocks from miners to other nodes.

For the most part, these services are only usefully performed by full nodes that are listening on port 8333. The more full nodes that accept incoming connections there are, the more users the Bitcoin network can support. Although if there is ever a shortage, lots of archival nodes can be easily created by cheaply renting VPS or AWS space.

=== Some are incentivizing it ===
Bitnodes ran a program to incentivize full node operators until the end of 2015.<ref>[https://bitcoinmagazine.com/19620/bitnodes-project-issues-first-incentives-node-operators/ Bitnodes Project Issues First Incentives For Node Operators by Joel Dalas] of [http://bitcoinmagazine.com/ Bitcoin Magazine]; cf. https://blog.bitcoinfoundation.org/bitnodes-project-2015-q1-report-peer-index-and-incentivized-full-nodes/</ref>

== How to run a full node ==

If you run the [[Bitcoin Core]]/[[bitcoind]] wallet, you are running a full node. If you open port 8333, you will contribute to the network's capacity. If you actually use the wallet feature, or if you use a lightweight client like [[MultiBit]] but configure it to connect exclusively to your full node, then you will contribute to the network's economic strength and receive protection from some possible attacks against lightweight nodes.

There are a few alternate full node implementations, but they are not recommended for serious use because it is currently difficult to determine whether they implement the consensus rules with 100% accuracy. Even very slight inaccuracies could cause serious problems for the users of these alternate clients. Example of implementations [[libbitcoin]], [[btcd]], [https://bitcoinfo.org/bitcoin-information/full-node.html a list of other Full Nodes].

=== Tips and tricks for running a node ===

For [[Bitcoin Core]]:

* Bandwidth consumption can be reduced using this guide: https://btcinformation.org/en/full-node#reduce-traffic

* Requirement for disk space can be reduced using this guide: https://btcinformation.org/en/full-node#reduce-storage See also the [https://github.com/bitcoin/bitcoin/blob/v0.11.0/doc/release-notes.md#block-file-pruning release notes which explain pruning].

* This site has a nice predefined template for generating bitcoin config files https://jlopp.github.io/bitcoin-core-config-generator/

* Improve sync speed by increasing the dbcache value in configuration. This value controls how many megabytes of RAM to use for the database cache, increase it to as much as your hardware allows to reduce the disk operations and increase speed.

* To store the blockchain files on an external hard drive use <tt>-datadir</tt>. e.g. <tt>-datadir=/path/to/your/bitcoin/directory</tt>.

* Store the chainstate directory on an SSD drive to improve the speed.<ref>[https://www.reddit.com/r/Bitcoin/comments/7iaa3t/if_you_run_a_full_node_on_a_hdd_put_your/ If you run a full node on a hdd put your chainstate directory on an external ssd].</ref>
** See [[Splitting the data directory]]

See Also: [[Running Bitcoin]]

== See Also ==

* [[Clearing Up Misconceptions About Full Nodes]]

* [[Why Your Business Should Use a Full Node to Accept Bitcoin]]

* [[Bitcoin is not ruled by miners]]

==References==
<references />

[[Category:Technical]]
[[Category:Privacy]]

{{Bitcoin Core documentation}}

File:BitcoinCore-node.jpg

2025-12-14T10:46:24Z

NotATether: The main window of Bitcoin Core on Windows.

== Summary ==
The main window of Bitcoin Core on Windows.
== Licensing ==
{{subst:nld}}

Securing Your Computer

2025-12-13T15:06:59Z

NotATether: Direct Windows users to use BitLocker

If you want to [[Secure Trading|trade securely]], you must observe some security precautions. Along with the concerns of conventional online banking, trading with Bitcoins also requires physically securing your computer.

==Operating System==
Even the best operating system is only as good as it is maintained and configured.

===Updates===
In general, make sure to install all the safety-related updates from the manufacturer. Modern operating systems have an automatic update feature that is essential to activate. This ensures that available updates are always installed as soon as possible. This is important because as soon as the manufacturer patches a security issue, the error usually is already well known in certain circles long before the patch is released.

===Virus Protection===
To minimize the possibility of malicious software like viruses or trojans finding a home in your computer, it is important to install a functioning and current virus scanner.

Also it is important to realize the principle of "more is better" does not apply. Installing two, or even more, virus scanners on a computer can greatly reduce system stability, speed, and usability. For home users, there is a variety of virus scanners that are free for home use that are completely sufficient.

For more detailed information please visit the corresponding [http://en.wikipedia.org/wiki/Antivirus_software Wikipedia article].

===Firewall===
A firewall protects against outside access to your computer and installed applications, preventing unauthorized access to the network. Since no virus scanner can detect all potential pests, a firewall is therefore a useful protection against trojans, for if one does happen to get installed, it will be unable to transmit passwords or similar information.

If you do not have a well-configured hardware firewall, or do not know if you are behind one, it is absolutely necessary to install and configure a software firewall (one typically comes built-in to the operating system). A software firewall is a useful addition to a hardware firewall, since there is a possibility that another computer within your network is already infected, or has some other nefarious intention.

Also, a firewall is only as good as it is configured. The rule "the stricter the better" definitely applies. It should only allow applications that you know and trust to access the network. Some firewalls will recognize the ports used by particular applications to communicate with the outside world. If this is not the case, you should consult your firewall's documentation for direction on how to open a port. The port that Bitcoin uses is port 8333.

For more detailed information, please visit the corresponding [http://en.wikipedia.org/wiki/Firewall_(computing) Wikipedia article].

==Theft==
To ensure [[Secure Trading|secure trading]], the physical components of your computer, as well as any media (USB stick, external hard drive, etc) on which your wallet is stored, must be secured.

===Anti-theft===
Many laptops and even some desktop computers can be secured with a cable designed to prevent theft. Such cables are named after the largest manufacturer of security cables, Kensington, and are designed to connect to the computer's "Kensington Security Slot". Use of such a security cable allows a computer to be "chained" to an immovable object such as a heating pipe, or a specially mounted bracket. This will not make theft impossible, but makes theft incredibly difficult without the proper set of tools.

===Encryption===
Since computers can not always be chained up everywhere, and even the best security cable is not immune to bolt cutters, it is important that the medium on which you store your [[wallet]] be encrypted. See [https://en.wikipedia.org/wiki/Comparison_of_disk_encryption_software here] a list of available encryption software. If you are using Windows, the simplest option is to use [https://support.microsoft.com/en-us/windows/bitlocker-drive-encryption-76b92ac9-1040-48d6-9f5f-d14b3c5fa178 BitLocker] which is bundled with Pro versions of the operating system.

Although the computer might have been stolen, at least the thief does not have access to your wallet and cannot send Bitcoins in your name. Despite being encrypted and safe from prying eyes, your wallet is still irretrievably lost, which makes it important to regularly keep a [[backup]] of your wallet.

With processors always getting faster, brute force attacks on passwords are getting easier and easier. To stem this advance in password-breaking, a good-length (>12 characters), complex password with special characters should be used.

Users need to be informed, understand, and be up-to-date with the concepts behind password cracking in order to know the nature of the password they should choose. [http://arstechnica.com/security/2013/10/how-the-bible-and-youtube-are-fueling-the-next-frontier-of-password-cracking/ This Ars Technica article] is very informative about this. In some cases and some algorithms, an extremely long ''random'' password with many types of ''random'' characters is required. Even passwords like [http://arstechnica.com/security/2013/10/izmy-p55w0rd-saph/ these] aren't immune.

==See Also==
*[[Securing your wallet]]
*[[Secure Trading]]

[[de:Sichern des Computers]]

[[Category:Instructional]]

Secure Trading

2025-12-13T15:03:59Z

NotATether: Update Windows instructions for installing GPG

Bitcoin users may want to trade bitcoin directly with each other in what is known as an over-the-counter market. This topic is a guide on how to set up your online identity and includes some [[Best Practices|best practices]] for trading with others in the Bitcoin community.

Peer-to-peer exchanges such as [[Bisq]] and [[Hodl Hodl]] can be good alternative platforms for direct KYC-less trading. For a full list of no-KYC exchanges see: https://github.com/cointastical/P2P-Trading-Exchanges/

==Introduction==
Within the Bitcoin community, individuals should be careful with their security and identity, primarily for two reasons:
# At this time, there is little in the way of law enforcement. No court has dealt directly with a significant theft of bitcoins or determined Bitcoin's legal status. Bitcoin users are for the most part, on their own.
# In lieu of legal action and lack of community trust outside the Bitcoin system itself, one's reputation has become the focus for building trust relationships with others in the community. Traders will take very little risk with new users who have not proven themselves (as one user can easily commit continuous fraud using many different identities.

The Bitcoin community uses a few tools to help protect privacy, and thus identity. The first and most important is a [[Securing Your Computer|secure computer]]. 

'''Before proceeding please make sure you have completed the [[Securing Your Computer]] guide; this guide assumes that your computer is secure both physically and in software.'''

If you are trading within Canada you are encouraged to use Interac e-transfer and Clearcoin (now closed) as outlined on [[Secure Trading-CAD-interac|this page]].

==Creating a secure identity==
The first step is to create a cryptographically secure public-private key-pair. This will be used as the basis of keeping both your wallet (see [[Securing your wallet]]) and your identity secure.

===Creating your first [http://en.wikipedia.org/wiki/Pretty_Good_Privacy PGP] key-pair===
A PGP key-pair serves two very important functions:
# To sign information with an unforgeable signature
# To decrypt things that other people encrypt for you

This allows you to both conduct business privately (encryption), and give out promises that you cannot deny making (signature).
==== Installing GPG ====
Virtually all GNU/Linux distributions include [http://en.wikipedia.org/wiki/GNU_Privacy_Guard GPG] in their default configurations, though if it isn't, you need to install it from your package manager. Windows and macOS users will need to install additional software.

===== Microsoft Windows:=====
On Windows 10 (version 1903 or later) and Windows 11, the simplest approach is to use GPG through [https://en.wikipedia.org/wiki/Windows%20Subsystem%20for%20Linux Windows Subsystem for Linux (WSL)].

WSL provides a real Linux userland running directly on Windows, allowing users to install and run the native packages. This approach is preferred over older MSYS-based packages, which may ship outdated or limited versions of GPG.

WSL must be enabled before installing a Linux distribution. From an elevated command prompt:

<code>wsl.exe --install</code>

This command enables WSL and installs the latest LTS version of Ubuntu. A system reboot may be required.

Alternatively, or if you wish to choose a specific distribution:

* Open the '''Microsoft Store'''
* Search for a Linux distribution (for example: ''Ubuntu'')
* Select the distribution (e.g. ''Ubuntu 22.04 LTS'')
* Click '''Install'''
* Launch the distribution after installation to complete initial setup (username/password). A reboot may be required.

Once inside the Linux shell, install GnuPG using the distribution’s package manager.

Older versions of Windows can install the [https://www.gpg4win.org/ GPG4Win] program to use GPG. In addition to a graphical user interface, it installs and adds gpg.exe to the PATH environment automatically, so that it may be invoked from new Windows Command Prompt (cmd) windows.

It is possible that some other software on your system has installed GPG before. If you think this may be the case, it is advised to use the search tool or command prompt to find or run GPG respectively.

==== Setting up OpenPGP email ====
Once you have GPG installed on your system, it is recommended that you use Thunderbird that works on both Windows and Linux systems:

===== All: =====
# Install Thunderbird: https://www.mozillamessaging.com/en-GB/
# Setup your email account with Thunderbird.
# Install the Enigmail plugin for Thunderbird: https://addons.mozilla.org/en-US/thunderbird/addon/enigmail/ 

Upon loading Enigmail, Thunderbird will ask you to make a new ‘identity,’ follow this wizard and you will have created your identity. 
You should backup your private key in a secure place. 
Secondary, you should create a revocation certificate and store that in a different secure place (maybe print it out and store it in your fire safe).

===Register with [#bitcoin-otc]===
Follow the guide here: http://wiki.bitcoin-otc.com/wiki/Using_bitcoin-otc

===Register the same username at the popular places:===
* [[Bitcoin Forum]]
* [[Bitcoin.it_Wiki|Bitcoin Wiki]]
* [[Bitcoin Wiki:Community_portal#IRC_Chat|Freenode IRC]]
Use a strong and different password for each of these places, keeping your passwords in a secure place. This will allow other people in the community to track you across the different Bitcoin related sites. Also making identity theft online more challenging.

==Best Practices with trading==

===Use an Escrow Service===
Trading can benefit from an [[:Category:Escrow_services|escrow service]] such that bitcoins are held by a third party and disbursed only after contract terms have been met. Individuals willing to act as independent escrow brokers can be found in bitcoin's community.

Use of 2-of-3 [[Multisignature|multisignature]] escrow eliminates the risk of the arbitrator stealing the held coins, or losing them to malware or hackers.

===Make sure both parties agree to the terms of the trade with signed messages===
* Get a PGP signed quote, and check the signature.
* Send a PGP signed receipt.
This allows either party to go public if the trade has become sour and stops your trading partner from claiming the details of the agreement were somehow different. 

====Worked Example====

# Buyer and seller agree on the terms of contract
# Both choose a arbitrator
# Buyer, seller and arbitrator create public keys and use them to create a 2-of-3 [[Multisignature|multisig]] address. The public keys are added to the contract and PGP-signed.
# Buyer sends bitcoins as payment to the multisig address.
# Seller [[Confirmation#How_Many_Confirmations_Is_Enough|waits for a number of confirmations]] and then hands over or ships the product.
# After receiving the product and verifying its integrity, buyer and seller sign a transaction to transfer bitcoins to the seller.
# If there is a dispute, the arbitrator uses his third key to tie-break after reviewing all the evidence and following the contract.

===Decentralised/social exchanges===
Using a service such as [[Bitcoin-otc|Bitcoin OTC]] or [[CoinTouch]], you can find friends of friends that trade crypto currency, and trade with them directly. Remember to verify the counterparty using more than one means of contact (e.g. Facebook message and phone call)

====Bitcoin-OTC====
The [[Bitcoin-otc|Bitcoin OTC]] acts as a secure 'Address Book' within the bitcoin community.
* Always require the user to become registered with #bitcoin-otc.
* Require a signed message from the fingerprint quoted at: http://bitcoin-otc.com/viewgpg.php
* Follow additional [http://wiki.bitcoin-otc.com/wiki/Using_bitcoin-otc#Risk_of_fraud recommendations] for avoiding fraud.

=====Using the Web-Of-Trust=====
One of the key features of the Bitcoin OTC is the Web of Trust, this allows users to 'rate' each other. One can have more confidence trading with a user that has many good ratings.
* http://bitcoin-otc.com/viewratings.php

Search the Bitcoin Forum for the username of the person that you are trading with. Check if the user has provided constructive and useful advice to other parties. And, most importantly, check for any claims that the user has scammed.

==See Also==

* [[Securing online services]]
* [http://bitcointalk.org/index.php?topic=137272.0 Tips for Local Trading]

[[de:Sicheres_Handeln]]
[[zh-cn:交易安全]]

[[Category:Instructional]]
[[Category:Security]]

Blockstream

2025-12-13T06:43:40Z

NotATether: fix wording

{{Infobox company
| name = Blockstream
| image = [[File:Blockstream_logo.png|thumb|upright=0.85]]
| image_caption = Blockstream logo
| industry = Blockchain technology Cryptocurrency
| website = [https://blockstream.com/ blockstream.com]
| twitter = Blockstream
}}

'''Blockstream''' is a blockchain technology company focused on building infrastructure for Bitcoin and digital assets.<ref>{{cite web |title=About Blockstream |url=https://blockstream.com/about/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref> Founded in 2014, the company develops products and services aimed at enhancing the Bitcoin ecosystem, including [[Sidechain|sidechains]], layer-2 solutions, wallets, [[Hardware wallet|hardware devices]], and data broadcasting services.

The company is headquartered in Victoria, British Columbia, Canada, with offices and staff worldwide.

== History ==
Blockstream was founded in 2014 by a group of prominent Bitcoin developers and cryptographers, including [[Adam Back]] (inventor of [[Hashcash]]), Gregory Maxwell, Pieter Wuille, Austin Hill, and others. Adam Back serves as CEO.

The company has raised significant funding, including over $210 million in a Series B round in 2021, achieving a valuation of $3.2 billion at that time.<ref>{{cite web |title=Blockstream Raises $210 Million, Now Valued At $3.2 Billion |url=https://www.greenhausblockchain.com/blockstream-raises-210-million-now-valued-at-3-2-billion/ |publisher=GreenHaus Blockchain |date=August 24, 2021 |access-date=December 13, 2025}}</ref><ref>{{cite web |title=Series B - Blockstream |url=https://www.crunchbase.com/funding_round/blockstream-series-b--a09cee6b |publisher=Crunchbase |date=August 24, 2021 |access-date=December 13, 2025}}</ref> Additional investments have occurred since, with ongoing developments in Bitcoin infrastructure.<ref>{{cite web |title=Press Releases |url=https://blockstream.com/press-releases/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref>

== Products and services ==
Blockstream's key offerings include:
* '''Liquid Network''': A federated Bitcoin sidechain for faster settlements, confidential transactions, and asset issuance.
* '''Blockstream Green''': A multi-platform, open-source Bitcoin and Liquid wallet.<ref>{{cite web |title=Blockstream App |url=https://blockstream.com/app/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Blockstream Jade''': An open-source hardware wallet for secure storage of Bitcoin and Liquid assets.<ref>{{cite web |title=Blockstream Jade |url=https://blockstream.com/jade/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Core Lightning''': An implementation of the Lightning Network protocol.
* '''Blockstream Satellite''': A service broadcasting the Bitcoin blockchain via satellite for offline or remote access.

The company also contributes significantly to [[Bitcoin Core]] development and focuses on scalability, privacy, and interoperability solutions.

== References ==
{{reflist}}

[[Category:Companies]]

Blockstream

2025-12-13T06:40:44Z

NotATether: add wiki links

{{Infobox company
| name = Blockstream
| image = [[File:Blockstream_logo.png|thumb|upright=0.85]]
| image_caption = Blockstream logo
| industry = Blockchain technology Cryptocurrency
| website = [https://blockstream.com/ blockstream.com]
| twitter = Blockstream
}}

'''Blockstream''' is a blockchain technology company focused on building infrastructure for Bitcoin and digital assets.<ref>{{cite web |title=About Blockstream |url=https://blockstream.com/about/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref> Founded in 2014, the company develops products and services aimed at enhancing the Bitcoin ecosystem, including [[Sidechain|sidechains]], layer-2 solutions, wallets, [[Hardware wallet|hardware devices]], and data broadcasting services.

The company is headquartered in Victoria, British Columbia, Canada, with offices and staff worldwide.

== History ==
Blockstream was founded in 2014 by a group of prominent Bitcoin developers and cryptographers, including [[Adam Back]] (inventor of [[Hashcash]]), Gregory Maxwell, Pieter Wuille, Austin Hill, and others. Adam Back serves as CEO.

The company has raised significant funding, including over $210 million in a Series B round in 2021, achieving a valuation of $3.2 billion at that time.<ref>{{cite web |title=Blockstream Raises $210 Million, Now Valued At $3.2 Billion |url=https://www.greenhausblockchain.com/blockstream-raises-210-million-now-valued-at-3-2-billion/ |publisher=GreenHaus Blockchain |date=August 24, 2021 |access-date=December 13, 2025}}</ref><ref>{{cite web |title=Series B - Blockstream |url=https://www.crunchbase.com/funding_round/blockstream-series-b--a09cee6b |publisher=Crunchbase |date=August 24, 2021 |access-date=December 13, 2025}}</ref> Additional funding rounds have occurred since, with ongoing developments in Bitcoin infrastructure.<ref>{{cite web |title=Press Releases |url=https://blockstream.com/press-releases/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref>

== Products and services ==
Blockstream's key offerings include:
* '''Liquid Network''': A federated Bitcoin sidechain for faster settlements, confidential transactions, and asset issuance.
* '''Blockstream Green''': A multi-platform, open-source Bitcoin and Liquid wallet.<ref>{{cite web |title=Blockstream App |url=https://blockstream.com/app/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Blockstream Jade''': An open-source hardware wallet for secure storage of Bitcoin and Liquid assets.<ref>{{cite web |title=Blockstream Jade |url=https://blockstream.com/jade/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Core Lightning''': An implementation of the Lightning Network protocol.
* '''Blockstream Satellite''': A service broadcasting the Bitcoin blockchain via satellite for offline or remote access.

The company also contributes significantly to [[Bitcoin Core]] development and focuses on scalability, privacy, and interoperability solutions.

== References ==
{{reflist}}

[[Category:Companies]]

Blockstream

2025-12-13T06:38:22Z

NotATether: Add Blockstream page

{{Infobox company
| name = Blockstream
| image = [[File:Blockstream_logo.png|thumb|upright=0.85]]
| image_caption = Blockstream logo
| industry = Blockchain technology Cryptocurrency
| website = [https://blockstream.com/ blockstream.com]
| twitter = Blockstream
}}

'''Blockstream''' is a blockchain technology company focused on building infrastructure for Bitcoin and digital assets.<ref>{{cite web |title=About Blockstream |url=https://blockstream.com/about/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref> Founded in 2014, the company develops products and services aimed at enhancing the Bitcoin ecosystem, including sidechains, layer-2 solutions, wallets, hardware devices, and data broadcasting services.

The company is headquartered in Victoria, British Columbia, Canada, with offices and staff worldwide.

== History ==
Blockstream was founded in 2014 by a group of prominent Bitcoin developers and cryptographers, including Adam Back (inventor of Hashcash), Gregory Maxwell, Pieter Wuille, Austin Hill, and others. Adam Back serves as CEO.

The company has raised significant funding, including over $210 million in a Series B round in 2021, achieving a valuation of $3.2 billion at that time.<ref>{{cite web |title=Blockstream Raises $210 Million, Now Valued At $3.2 Billion |url=https://www.greenhausblockchain.com/blockstream-raises-210-million-now-valued-at-3-2-billion/ |publisher=GreenHaus Blockchain |date=August 24, 2021 |access-date=December 13, 2025}}</ref><ref>{{cite web |title=Series B - Blockstream |url=https://www.crunchbase.com/funding_round/blockstream-series-b--a09cee6b |publisher=Crunchbase |date=August 24, 2021 |access-date=December 13, 2025}}</ref> Additional funding rounds have occurred since, with ongoing developments in Bitcoin infrastructure.<ref>{{cite web |title=Press Releases |url=https://blockstream.com/press-releases/ |publisher=Blockstream Corporation |access-date=December 13, 2025}}</ref>

== Products and services ==
Blockstream's key offerings include:
* '''Liquid Network''': A federated Bitcoin sidechain for faster settlements, confidential transactions, and asset issuance.
* '''Blockstream Green''': A multi-platform, open-source Bitcoin and Liquid wallet.<ref>{{cite web |title=Blockstream App |url=https://blockstream.com/app/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Blockstream Jade''': An open-source hardware wallet for secure storage of Bitcoin and Liquid assets.<ref>{{cite web |title=Blockstream Jade |url=https://blockstream.com/jade/ |publisher=Blockstream |access-date=December 13, 2025}}</ref>
* '''Core Lightning''': An implementation of the Lightning Network protocol.
* '''Blockstream Satellite''': A service broadcasting the Bitcoin blockchain via satellite for offline or remote access.

The company also contributes significantly to Bitcoin Core development and focuses on scalability, privacy, and interoperability solutions.

== References ==
{{reflist}}

[[Category:Companies]]

File:Blockstream logo.png

2025-12-13T06:14:00Z

NotATether: Logo of Blockstream.

== Summary ==
Logo of Blockstream.

Namecoin block explorer

2025-12-13T05:59:59Z

NotATether: Change block chain browser to block explorer and add offline notice

The '''Namecoin block explorer''' [http://explorer.dot-bit.org/] was an online [[block explorer]] for [[Namecoin]].

In addition to block, transaction, and address details, the Namecoin block explorer displayed name operations and the effect of network fees on the number of coins outstanding.

The service has been offline since at least 2022.

[[Category:Block chain browsers]]

Block explorer

2025-12-13T05:55:56Z

NotATether: Add reference to past nomenclature of block chain browser

==Block Explorer==

A block explorer (also known as a blockchain explorer, or block chain browser) is a web application to view and query [https://en.bitcoin.it/wiki/Block blocks] <ref>Blockchain for dummies p 99 - Tiana Laurence - ISBN 978-1119365594</ref> working as a [https://en.bitcoin.it/wiki/Web_browser web browser] that is not connected to the internet, like Google Chrome, but to the [https://en.bitcoin.it/wiki/Blockchain Blockchain]. Their primary function is to allow everyone with an internet connection to track in real-time all the [https://en.bitcoin.it/wiki/Transaction_confirmation transactions] or interactions made by each [https://en.bitcoin.it/wiki/Cryptocurrency cryptocurrencies] holders, regardless of his or her level of knowledge and expertise. <ref>Blockchain Enabled Application p.21 - David Metcalf - ISBN 978-1484230800</ref>. However, although there are plenty of Explorer available, only a tiny minority are able to show the transaction using [https://en.bitcoin.it/wiki/Segregated_Witness SegWit] (Bitcoin bech32 addresses start with “bc1”) <ref>Blockchain: A Practical Guide to Developing Business, Law, and Technology Solutions 1st Edition p.19- Joseph J. Bambara - ISBN 978-1260115871</ref>

==The default view==

The default view in the main page generally provides in real time information about of all the last blocks that are being added to the blockchain, most often separated into six columns with this following informations:

'''Block height:''' <ref>Mastering Bitcoin p.28 - Andreas M. Antonopoulos - ISBN 978-1491954386</ref> block number since the Bitcoin [https://en.bitcoin.it/wiki/Genesis_block genesis block] was [https://en.bitcoin.it/wiki/Mining mined]. Each new mined block assumes an increase of one at the height of the block. Thus, the number 492800 in this column means this is the 492800th block mined in the whole history.

'''Age:''' the moment when the block was accepted by a miner and not when the user initiated a payment or transfer to another wallet.

'''[https://en.bitcoin.it/wiki/Transaction_confirmation Confirmation]:''' The most relevant information visible at a glance, the transaction status. If a transaction is «unconfirmed» or «pending», that means the transaction is in the Blockchain, but has not included in a block yet. In average, it takes typically 10 minutes for a bitcoin transaction to be confirmed. It will take about one hour to get «confirmed» by six confirmations.

'''Transaction list (TX):''' number of transactions included in the block. <ref>Blockchain: A Practical Guide to Developing Business, Law, and Technology Solutions 1st Edition p.18- Joseph J. Bambara - ISBN 978-1260115871</ref>

'''Reward:''' the reward for those (miners) who mined the block.

'''Mined by:''' name of the miner who mined this block. Usually a pool of miners who had been involved in.

'''Size:''' size of the transaction obtained by adding the sizes of each transactions included in the block. This data is always provided in bytes.

==The browser==

In the same way as with an Internet browser, the user needs to enter a request to begin his search. It can be a transaction hash or TXID <ref>beginning-blockchain-guide-building-solutions p.278 - Bikramaditya Singhal - ISBN 978-1484234433</ref>(sequence of 64 characters hexadecimal (0 to 9 and a to f) numbers used to uniquely identify a particular transaction) or a block height for example. Automatically, a page containing all the details about the transaction is loaded according to the request. Advanced information contains all the movements in this transaction and is only available at the user's request. Most of the time, a bitcoin transaction has several input and output [https://en.bitcoin.it/wiki/Bitcoin_address addresses] insofar as it allows a sender to save time and money by sending to several addresses at once. All the following data will be displayed:

'''TXID:''' as mentioned above

'''Input:''' transaction inputs are pointers to UTXO <ref>Blockchain Enabled Application p.18 - David Metcalf - ISBN 978-1484230800</ref>. They point to a specific UTXO by reference to the transaction hash and sequence number where the UTXO is recorded in the blockchain.

'''Output:''' contains instructions for sending bitcoins <ref>Blockchain Enabled Application p.18 - David Metcalf - ISBN 978-1484230800</ref>.

'''Value:''' the number of Satoshi (1 BTC = 100,000,000 Satoshi) that this output will be worth when claimed.

'''ScriptPubKey:''' the second half of a script. There can be more than one output. Because each output from one transaction can only ever be referenced once by an input of a subsequent transaction, the entire combined input value needs to be sent in an output if the user doesn't want to lose it. <ref>beginning-blockchain-guide-building-solutions p.201-202 - Bikramaditya Singhal - ISBN 978-1484234433</ref> If the input is worth 50 BTC but a consumer only want to send 25 BTC, Bitcoin will create two outputs worth 25 BTC. This section is divided into two parts. The first, the top line, showing the total amount that the recipient has to receive in BTC, known as the destination. And the other part, below, showing the amount of bitcoins back to the user that remains in the wallet and which can be used as a new input in a subsequent transaction. Any input bitcoins not redeemed in an output is considered a transaction fee.

'''Transaction Fees:''' most transactions include transaction fees, which compensate the bitcoin miners for securing the network. Transaction fees serve as an incentive to include (mine) a transaction into the next block and also as a disincentive against “spam” transactions or any kind of abuse of the system, by imposing a small cost on every transaction. Transaction fees are collected by the miner who mines the block that records the transaction on the blockchain. <ref>Mastering Bitcoin p.127 - Andreas M. Antonopoulos - ISBN 978-1491954386</ref>

'''Coinbase Data:''' This field must be between 2 and 100 bytes. Except for the first few bytes the rest of the coinbase data can be used by miners in any way they want; it is arbitrary data. In the genesis block, for example, Satoshi Nakamoto added the text “The Times 03/Jan/ 2009 Chancellor on brink of second bailout for banks” in the coinbase data, using it as a proof of the date and to convey a message. Currently, miners use the coinbase data to include extra nonce values and strings identifying the mining pool. <ref>Mastering Bitcoin p.225 - Andreas M. Antonopoulos - ISBN 978-1491954386</ref>

==List of blockchain explorers==

Unless otherwise noted, all explorers support segwit addresses.

* https://mempool.space Open-source Bitcoin Explorer
* https://bitaps.com
* https://mempool.ninja Development version of mempool.space
* https://blockstream.info/
* https://bitcoinchain.com
* https://bitinfocharts.com/bitcoin
* https://blockchain.info
* https://blockchair.com/
* https://btcscan.org/
* https://bitcoinexplorer.org
* https://btc.com/
* https://tokenview.io
* https://chain.so/BTC
* https://chainz.cryptoid.info/btc
* https://insight.bitpay.com
* https://live.blockcypher.com/btc
* https://blockpath.com/
* https://www.oklink.com/
* https://bitcoinchain.com/block_explorer
* https://www.blockexplorer.com/
* https://cryptomus.com/explorer
* https://www.blockonomics.co
* https://blockexplorer.one
* https://yogh.io/landing/
* https://be.anyone.eu.org - local [https://bitcoinexplorer.org/ BitcoinExplorer] instance
* https://bitref.com

==References==
<references />

BlockExplorer.com

2025-12-13T05:54:58Z

NotATether: Change references from "block chain browser" to "block explorer"

'''Bitcoin Block Explorer''' is an online [[block explorer]] which displays the contents of individual [[Bitcoin]] [[blocks]] and [[transactions]] and the transaction histories and balances of [[Address|addresses]]. It was originally written by theymos, but it is now operated by Liraz Siri.

Each object is displayed in human-readable form, as a web page, and is given a URL. By using hyperlinks, it allows users to switch from seeing one piece of data to a related one, with a single click. Clicking on the hash of an object, will move to the page that displays its data. This way for instance, you can switch from looking at a transaction, to looking at the previous transaction which gave this transaction its inputs. All block data is visible, in human-readable or machine-readable forms, and even some information that is not actually part of blocks.

It is mainly aimed at advanced users who already know what blocks are and what kind of information they contain, but a lot of helpful information is provided in tool-tips.

A listing of "strange transactions" is displayed in the main page, along with listings of the latest and largest transactions.

Bitcoin Block Explorer can also display information from the [[Testnet]].

==History==

Many of the real-time stats pages existed before Bitcoin Block Explorer at http://theymos.ath.cx:64150/q. ''getdifficulty'' and ''getblockcount'' were created around July 2010, with ''decimaltarget'', ''probability'', ''hashestowin'', ''nextretarget'', ''totalbc'', and ''bcperblock'' coming soon after. These pages were made in response to block and difficulty values being "hard-coded" into text on the old wiki, which quickly made the information obsolete.

Bitcoin Block Explorer was first made available around November 2010 at http://theymos.ath.cx:64150/bbe. It was initially meant to be the Bitcoin equivalent of [http://torstatus.blutmagie.de/ TorStatus], dumping all important data about the network. After it became much more popular than the real-time stats pages, BBE was moved to http://blockexplorer.com/, and real-time-stats were moved to http://blockexplorer.com/q.

==Interfacing with BBE==

Use the [http://blockexplorer.com/q query pages] such as ''getreceivedbyaddress'' wherever possible. Note that these pages do not send a trailing newline, which may cause problems with your HTTP-fetching tool. When an error occurs, the result will begin with "ERROR:", followed by the error text. Your detection of "ERROR" must be case-insensitive. An empty result is also an error. Non-fatal errors will print query results on the next line after the error, though using this data is inadvisable.

To get block or transaction info, first find the hash of the item. This is done by using the search tool, which is accessible through a GET/HEAD request. For example, to get the hash of block number 444:
$ telnet blockexplorer.com 80
HEAD /search/444 HTTP/1.1
Host: blockexplorer.com

HTTP/1.1 302 Found
...
Location: http://blockexplorer.com/block/00000000cff43a64ec00bea1...
The hash is in the URL listed in the "location" header. Use it to get the JSON raw block:
http://blockexplorer.com/rawblock/00000000cff43a64ec00bea1...
Transactions use a URL like this:
http://blockexplorer.com/rawtx/cd5a933b2aec79c02f7ce36222930d4c85...

If the search returns any status code other than 302, then the search is bad. A status code of 200 indicates that the search was ambiguous, and the page body will contain links to the choices. [http://blockexplorer.com/search/0x111111 Example of search ambiguity]. A search with no search terms will 302-redirect to the home page. Searches for valid block numbers will always redirect to the block with that number (ignoring all other search types), though you can force BBE to assume a hex value by preceding it with "0x".

The shortlinks at the top of most pages are similar to searches. It is possible for shortlinks to be ambiguous, and they will likewise return a 200 status code in that case.

Unfortunately, the JSON raw block/tx pages omit a lot of important information, and there is no similar page for addresses. A full XML interface is planned. Scraping the HTML pages is not recommended, as the layout can change at any time.

==See Also==

* [[:Category:Block chain browsers|Block chain browsers]] directory

== External Links ==

* [http://blockexplorer.com/ Bitcoin Block Explorer main website]
* [http://blockexplorer.com/testnet Version for testnet]
* [http://blockexplorer.com/q Realtime stats and other queries] (RESTful)

[[Category:Services]]
[[Category:Block chain browsers]]