Bitcoin Wiki - User contributions [en]

Passphrase generation

2026-07-31T06:49:27Z

NotATether: Bump passphrase strength requirements

In various places in Bitcoin, it is important to generate secure passwords/passphrases. Security is especially important in Bitcoin because if your BTC is stolen, there is often no recourse. Bitcoin transactions cannot be reversed.

==Strength==

There are two very different use-cases for passwords in Bitcoin. The first and more common is an "offline passphrase". With an offline passphrase, something prevents an attacker from trying to guess your passphrase as fast as he might like.

Examples include:

* Website passwords. The website will rate-limit attempts on your password.
* Wallet passphrases. An attacker needs both the wallet file and your wallet passphrase.
* Hardware wallet PIN. An attacker needs both the hardware wallet and your PIN.

All of the advice you've ever heard about password security has been for the offline password use-case.

The second use-case is an "online passphrase", where the passphrase is essentially the ''only'' thing protecting your BTC. In this case, your passphrase much be ''massively'' more secure than usual, and you '''can not''' rely on any password-creation advice you've ever heard.

For use cases that are vulnerable to a global passphrase cracking search, imagine that the entire world could be constantly trying to crack your passphrase, billions of attempts per second, all the time and with no restriction. This is not a normal situation outside of Bitcoin.

Examples of keys that could be cracked by a global search:

* The seed/mnemonic of an HD wallet.
* The passphrase on a wallet file that has become public, or that an attacker has otherwise gained access to.
* The input to a "brain wallet". ('''Warning:''' it is very strongly recommended that you not attempt to use a brain wallet.)
* Any wallet encrypted with a dictionary password or any other easy-to-guess password.

Example of keys that could be cracked by a targeted search:

* The passphrase on a wallet file that may become public, or that an attacker could gain access to.
* The input to a secure "brain wallet" with e-mail salting, and an expensive Key Derivation Function.
* Seed phrases stored in your e-mail.

=== Standards for offline passphrases ===

Between 64 and 80 bits of entropy seems reasonable. The password must be totally random (see later sections on generation). Hardware wallets have additional protections, and it's OK that they often allow only a short PIN. However it is preferrable to use more entropy.

This corresponds to the following password/passphrase lengths:

* Digits only: 20-25 digits
* Hexadecimal: 16-20 characters
* All lowercase or all uppercase letters: 14-18 characters
* All lowercase or all uppercase letters + numbers: 13-16 characters
* Mixed case letters: 12-15 characters
* Mixed case letters + numbers: 11-14 characters
* All standard keyboard characters: 9-11 characters
* Diceware words: 5-7 words
* Random English words (100,000-word wordlist): 4-5 words

=== Standards for online passphrases ===

The most common case of an online passphrase in Bitcoin is the mnemonic for an HD wallet seed, but a good wallet should securely generate it for you (this is the several-word mnemonic that most wallets tell you to write down when first run), assuming it has not been tampered with.

In case you need to manually generate an online passphrase, 128 bits of entropy is required. The passphrase must be totally random (see later sections on generation). Nowadays with more powerful GPU clusters available, it is mandatory to use this kind of strong passphrase.

This corresponds to the following password/passphrase lengths:

* Digits only: 39 digits
* Hexadecimal: 32 characters
* All lowercase or all uppercase letters: 28 characters
* All lowercase or all uppercase letters + numbers: 25 characters
* Mixed case letters: 23 characters
* Mixed case letters + numbers: 22 characters
* All standard keyboard characters: 20 characters
* Diceware words: 10 words
* Random English words (100,000-word wordlist): 8 words

== Risks of automatic seed/passphrase generation ==

Automatic wallet seed/passphrase generation is only secure using:

#'''Faithful wallet software''': that has not been maliciously tampered with. If you haven't compiled wallet software yourself on a trustworthy computer running a trustworthy compiler, trustworthy source code is no guarantee for a trustworthy binary. See the [http://wiki.c2.com/?TheKenThompsonHack Ken Thompson hack] for details. Wallets with a deterministic build process (e.g., Bitcoin Core) are more resistant to attack.

#'''Faithful RNG''': An RNG ([https://en.wikipedia.org/wiki/Random_number_generation Random Number Generator]) may be implemented in software, hardware or both. Wallet software relies on the security of the RNG, to generate your wallet's private keys securely. An insecure RNG may create wallet keys that can later be recreated by an attacker, by generating psuedo-randomness that would seem statistically indistinguishable from true randomness yet still be predictable to an advanced attacker. An RNG may become insecure as a result of malicious weakening or an unintentional mistake. This failure mode is common to any wallet generation procedure in which the true randomness of the source of entropy being used can not be verified.

#'''Faithful hardware''': software is executed by hardware. Unfaithful hardware may execute faithful software unfaithfully. This would be especially difficult to detect for computations where the final output is non-deterministic, such as an unfaithful hardware execution of Random Number Generator routines. The risk of such an attack is increased by the opaqueness of hardware implementation, and the centralized capital intensive nature of hardware manufacturing, making hardware companies more vulnerable to coercion, especially in undemocratic countries where most hardware manufacturing currently takes place.

For high risk applications, a pair of [http://rpg.stackexchange.com/questions/70802/how-can-i-test-whether-a-die-is-fair fair dice] can provide a simpler, verifiably secure source of entropy.

==How not to generate passphrases==

Humans are ''really, really'' bad at generating passphrases on their own. Don't try it. If at any step in the passphrase-generation process your brain is being used to choose something at random or randomize something, then you're doing it wrong.

Do not take words out of a book or other work. The words must be absolutely random.

Do not use the xkcd password generation method.

==Using dice==
Dice can be used as one way to generate random numbers and passwords. However, in order to achieve security, you must use them in a certain way.

===Secure dice===

Casual dice for board games are not shaped perfectly, and will be somewhat biased toward certain numbers. Special casino dice are available which do not have this flaw.

The extent to which slightly-biased dice actually affect real-world security depends on the use-case. For the use-cases on this page, if the dice is random enough to not notice its bias when playing games, then it is ''probably'' good enough.

===Generating passwords===

To generate passwords, write down a list of acceptable characters, and sequentially number each character starting from 1. For example, if you want to generate a 4-digit PIN, you would create a list like this:

<pre>1 0
2 1
...
10 9</pre>

If you wanted to generate a password with characters in [a-zA-Z], you would create a list like this:
<pre>1 a
2 b
...
52 Z</pre>

Now you need to figure out how many dice you're going to need to roll. Your dice should all have the same number of sides. If your character list has C characters, and each of your dice have S sides, then you need to roll logS(C) dice, rounded up. For example, log6(52) is about 2.2, which you round up to 3. So if your character list contains 52 characters, then you need to roll 3 6-sided dice.

Here, the dice are assumed to be numbered from 1 to S. If this is not the case, then you must create a system to translate the dice results into a range from 1 to S. For example, if you are dealing with 10-sided dice labeled from 0 to 9, then you can add 1 to the roll.

Roll the required number of dice and put them in a random order. Do not sort the dice from highest to lowest or anything like that. In fact, to prevent any personal bias from entering into the ordering, you may want to roll the dice and then put the dice into a line with your eyes closed.

Say that d0 is the rightmost dice you rolled, d1 is the second-from-rightmost dice you rolled, etc. Then the random number is:

1 + [(d0 - 1) × S0] + [(d1 - 1) × S1] + [(d2 - 1) × S2] + ...

For example, if we rolled 316 with 6-sided dice, this becomes:

1 + [(6 - 1) × 60] + [(1 - 1) × 61] + [(3 - 1) × 62] 
= 1 + [5 × 1] + [0 × 6] + [2 × 36] 
= 1 + 5 + 0 + 72 
= 78

So our random character would be the 78th character in the list.

'''Important''': If your number is larger than you need, then you must totally reroll for this character. Do not try to "wrap the numbers around" or keep only certain dice, as this results in a non-random distribution. (For the adventurous only: You can safely reduce the number of rerolls by pretending that the highest-order die has fewer sides. Eg. on a 6-sided die say that 1&4 = 1, 2&5 = 2, 3&6 = 3; or that 1&2&3 = 1 and 4&5&6 = 2. Still multiply it by the appropriate power of 6, not 3 or 2. But the die must be evenly divided, you must ensure that the maximum possible value is still greater than or equal to the highest-value character, and you must use the exact same treatment of the high-order die throughout the generation process.)

'''Important''': There are a variety of different ways to get a random number from multiple dice, but they are usually non-random. For example, ''adding'' dice would be very non-random. The above method ensures a random distribution if the dice themselves are random and if they are ordered randomly.

If the password is L characters long, then password has log2(CL) bits of entropy.

===Generating passphrases===

As above, but use a list of words instead of a list of characters.

Note that there is a risk when acquiring your wordlist of an attacker giving you a wordlist that has duplicated or highly similar words. For example, the wordlist might look like it contains 1 million words, but actually be the same 1000 words repeated over and over again. Or all of the words might have an "o" in the fourth position. Etc. This can cause you to significantly overestimate the security of your passphrase. Therefore, you must acquire your wordlist from a trusted source.

===Generating keys, seeds, and random numbers (Advanced)===

This section is mainly intended for programmers and advanced users.

Warning: it is considered unsafe to directly handle Bitcoin keys, as doing so is error-prone, and often causes people to send BTC into oblivion.

If you want to generate a large number for use as a key or seed, you can do the following.

First, decide how many bits of security you want. 128 bits is probably secure for most things. We will call this value B.

Next, roll logS(2B) dice, rounded up, where S is the number of sides per die. For example, with 6-sided dice you would need to roll 50 dice. Put the results right next to each other in a string of text, so for example if you roll 3, 2, 5, 6, 1, you'd start your string as "32561", and then continue on for a total of 50 digits. If your dice have enough sides to result in two-digit numbers, put a leading zero in front of single-digit numbers.

Then hash your string with a command like <tt>echo "32561..." |sha256sum</tt>. The resulting hash is your random number. If you want a 128-bit or 512-bit number use sha128sum or sha512sum, respectively. If you want some in-between number of bits, use the next larger hash size and then cut off the number where you need it.

You can generate any size of random number by combining the outputs. For example, let's say that you want 768 bits of randomness and for some reason you can only use sha256sum. You can do this like:

<pre>$ echo "32561..." |sha256sum
cf6a25b9ef81af3d2b1d6f62a9780637f5e27720cafb07bb0515228ada325ed5 -
$ echo "Last hash: cf6a25b9ef81af3d2b1d6f62a9780637f5e27720cafb07bb0515228ada325ed Orig entropy: 532561..." |sha256sum
6d7f302e01da0a7131377d57ee93aaff0b26ebd25e52c7dea0a5eeddabac151c -
$ echo "Last hash: 6d7f302e01da0a7131377d57ee93aaff0b26ebd25e52c7dea0a5eeddabac151c Orig entropy: 532561..." |sha256sum
e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 -</pre>

Then concatenate all of those hashes to get your final random number. In this example the result is <tt>cf6a25b...52b855</tt>.

'''Important''': When generating a stream of random numbers like this, you have to put your source entropy back in at each step.

If you want to generate a number in a range with a range size that is not a power of two, choose the next-largest power of two and select the correct number of bits based on that. If the resulting number is too large, '''discard''' all of those bits and grab new ones from the endless stream of random bits. Do not use the modulo operator, as that introduces a bias. For example, if you want to generate a number from 0 to 9 (range size = 10), select the next-higher power of 2, 16. If your random stream starts 0xA52F..., grab 4 bits (log2(16) = 4), giving 0xA = 10. This is outside of the range, so discard those bits and move onto the next 4 bits, 0x5 = 5. This is in the range, so the final result is 5.

When generating raw Bitcoin private keys: Although extremely unlikely to occur with a random 256-bit number, Bitcoin private keys cannot be equal to 0 or greater than to <tt>0xFFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE BAAEDCE6 AF48A03B BFD25E8C D0364140</tt>. When generating a Bitcoin private key, you should check that these conditions are met; if not, reroll the private key. Some software might allow you to use these invalid private keys, but doing so would be insecure.

==Using a computer==

Computers are good at generating secure random numbers, but you have to be careful to use the right commands. A lot of commands, programming language features, and snippets that you'll find online will give ''insecure'' random numbers which look random, but are predictable. For example, the C <tt>rand</tt> function, the Python <tt>random</tt> module, and the Windows <tt>%RANDOM%</tt> variable are all insecure random number sources.

'''Do not get your passwords from anything in a Web browser, even if the page says that it's using purely client-side JavaScript'''

===Linux===

There are many different packages for generating random passwords/passphrases on Linux, but none of them are installed by default on all Linux machines, so we will provide a method that uses more standard commands. If you would like a more concise and easy-to-use command, we recommend installing an actual password generator package.

The following command will generate a 20-character random password:

<pre>seq 126 |awk '{printf "%c", $0}' |grep -o '[a-zA-Z0-9]\|[[:punct:]]' | \
shuf --random-source=/dev/urandom --repeat --head-count=20 | tr --delete '\n'</pre>

Change <tt>-head-count=20</tt> to change the password length, and <tt><nowiki>[a-zA-Z0-9]\|[[:punct:]]</nowiki></tt> to change the character set. Note that this command will never use characters outside of ASCII, even if your grep pattern would select such characters.

To generate a passphrase made of words, create a file called <tt>words</tt> with one word per line and Unix-style line endings, and run:

<pre>shuf --random-source=/dev/urandom --repeat --head-count=7 words | tr '\n' ' '</pre>

Change <tt>-head-count=7</tt> to change the number of words.

Note that there is a risk when acquiring your wordlist of an attacker giving you a wordlist that has duplicated or highly similar words. For example, the wordlist might look like it contains 1 million words, but actually be the same 1000 words repeated over and over again. Or all of the words might have an "o" in the fourth position. Etc. This can cause you to significantly overestimate the security of your passphrase. Therefore, you must acquire your wordlist from a trusted source.

===Windows===

[http://keepass.info/ KeePass] includes a password generator, though not a word-based passphrase generator.

(If anyone knows of some better ones, edit this page to add it.)

== See also ==

* [https://github.com/dropbox/zxcvbn zxcvbn] - A realistic passphrase strength estimator

[[Category:Guides]]

Hardware wallet

2026-07-31T06:30:30Z

NotATether: Add Coldcard warning

A '''hardware wallet''' is a special type of [[wallet|bitcoin wallet]] which stores the user's private keys in a secure hardware device.

They have major advantages over standard software wallets:

* private keys are often stored in a protected area of a microcontroller, and cannot be transferred out of the device in plaintext
* immune to computer viruses that steal from software wallets
* can be used securely and interactively, private keys never need to touch potentially-vulnerable software
* much of the time, the software is open source, allowing a user to validate the entire operation of the device

This page is an attempt to summarize all the known developments of hardware wallets that can use Bitcoin as part of their operation.

== Security risks ==

To date there have been no verifiable incidents of Bitcoins stolen from hardware wallets. Hardware wallets are relatively new, but at least for the time being they have maintained a good track record, unlike the numerous incidents of Bitcoin theft from Internet-connected computers.

However, it's important to understand that hardware wallets are a high value target and depend on various assumptions holding true to maintain security. They are not a silver bullet, and there are several realistic ways in which a hardware wallet can fail to protect your Bitcoin. These risks need to be carefully considered when deciding how much trust to place in a hardware wallet, and which hardware wallet to buy.

How a hardware wallet could fail to protect your Bitcoin:

# '''Malware swaps recipient Bitcoin addresses''': a hardware wallet won't protect you from being tricked into sending Bitcoin to the wrong address. For example, malware on a PC could monitor for high value transactions and then swap out the recipient's authentic Bitcoin address for an address controlled by the attacker. When the stakes are high, multi factor (e.g., over the phone) confirmation of a recipient's Bitcoin address is recommended.
# '''Insecure RNG ([https://en.wikipedia.org/wiki/Random_number_generation Random Number Generator])''': hardware wallets rely on the security of an RNG, often embedded in hardware, to generate your wallet's private keys securely. Unfortunately, it is notoriously difficult to verify the true randomness of the RNG. An insecure RNG may create wallet keys that can later be recreated by an attacker, by generating psuedo-randomness that would seem statistically indistinguishable from true randomness yet still be predictable to an advanced attacker. An RNG may become insecure as a result of malicious weakening or an unintentional mistake. This failure mode is common to any wallet generation procedure in which the true randomness of the source of entropy being used can not be verified.
# '''Imperfect implementation''': the security of all computing devices relies on the quality of their implementation. Hardware wallets are no exception. Bugs at the software, firmware or hardware level may allow attackers to break into a hardware wallet and gain unauthorized access to secrets. Even if the design is perfect, proving the security of a hardware or software implementation is a very hard, mostly unsolved problem. To date, no wallet in existence is implemented using provably correct software.
# '''Compromised production process''': even a perfect software and hardware implementation of a hardware wallet would be vulnerable to a corrupt production process that introduces intentional or unintentional holes into the final product. The introduction of hardware backdoors is a [https://www.wired.com/2016/06/demonically-clever-backdoor-hides-inside-computer-chip/ real concern] for high risk financial and military applications.
# '''Compromised shipping process''': a compromised fulfillment process may substitute or modify secure devices for superficially identical but insecure replacements. Government programs that intercept hardware and modify them in route to insert backdoors [https://arstechnica.com/.../photos-of-an-nsa-upgrade-factory-show-cisco-router-getting-implant/ are known to exist].

In summary:

* While not a silver bullet hardware wallets can still be extremely useful, assuming you take care to use a good one: an authentic device manufactured by trustworthy, technically competent security experts with a good reputation (e.g., [[TREZOR]]).

* [[Cold storage]] solutions implemented with open source software and general purpose hardware (e.g., [[BitKey]], Pi Wallet), using a verifiable source of entropy such as physical dice may provide superior security for some use cases (e.g., long term savings).

== Connecting to a full node ==

By default, most hardware wallets instruct the user to connect to the manufacturer's own web interface. The web page cannot steal the user's private keys but can spy on them or trick them into accept fake payments.

Hardware wallets only keep the [[private keys]] safe and create spending transactions; they cannot tell you if you have actually received coins and in what quantity. Bitcoin's security model also requires that [[full node]] wallets are used. If not, somebody could pay you with a transaction of something other than bitcoin. If bitcoin is digital gold then a full node wallet is your own personal goldsmith who checks that the incoming payments are actually real. Also the third-party wallet will see all your [[Address|bitcoin addresses]] so this is very damaging to your privacy.

Most hardware wallets can be connected to [[Electrum]] bitcoin wallet. Electrum can be connected to your own [[Electrum#Electrum Personal Server|full node via a server]].

See also: [[Full node#Why should you use a full node wallet]]

== Commercial hardware wallets (ordered chronologically) ==

=== [[Trezor|Trezor One]] ===
[[File:Trezor-tx.jpg|300px|thumb|left|Confirming the transaction with Trezor]]

[[Trezor]] is a secure bitcoin storage and a transaction signing tool with open source hardware and software. The private keys are generated by the device and never leave it thus they cannot be accessed by a malware.

It uses a deterministic wallet structure which means it can hold an unlimited number of keys ([[BIP 0032]]/[[BIP 0044]]). A recovery seed is generated when the device is initialized. In case Trezor gets lost or stolen, all its contents can be recovered using this seed (private keys, bitcoin balance and transaction history) into a new device or another [[BIP 0039]]/[[BIP 0044]] compatible wallet.

Trezor also introduced a unique way of PIN entering preventing keyloggers from recording it even when entered on a compromised computer. An encryption passphrase can be set on top of the PIN protection. More passphrases can be used for plausible deniability.

Trezor One offers everything needed to protect cryptocurrency funds together with advanced features like [https://wiki.trezor.io/User_manual:Password_Manager Password manager] or [https://wiki.trezor.io/User_manual:Two-factor_Authentication_with_U2F U2F two-factor authorization].

''See also [[Hardware wallet#Trezor Model T|Trezor Model T - next-generation cryptocurrency hardware wallet]]''

[https://shop.trezor.io Trezor E-shop] | [https://wiki.trezor.io Trezor Wiki] | [https://trezor.io Trezor Homepage]

 

=== KeepKey: Your Private Bitcoin Vault ===
[[File:keepkey.jpg|300px|thumb|left|KeepKey showing a bitcoin transaction that needs to be manually approved.]]

KeepKey is a USB device that stores and secures your bitcoins. When you entrust KeepKey with your money, each and every bitcoin transaction you make must be reviewed and approved via it's OLED display and confirmation button.

KeepKey has a unique recovery feature utilizing a rotating cipher to restore private keys with a [[BIP 0039]] recovery seed. This means it is not necessary to store your private keys on KeepKey: the recovery process is secure enough so that KeepKey can be used as a transaction device for paper backups.

[https://www.keepkey.com keepkey.com]

 

=== Opendime: Bitcoin Credit Stick ===

[[file:Opendime.jpeg|300px|thumb|left|Opendime Package]]

The 1st Bitcoin Bearer Bond or just call it a "Bitcoin Stick"

Opendime is a small USB stick that allows you to spend Bitcoin like a dollar bill. Pass it along multiple times.
Connect to any USB to check balance. Unseal anytime to spend online. Trust no one.

It comes in the shape of a mini USB, and Opendime-ui.png|setting it up is astonishingly quick and simple. You plug OpenDime into a USB port, and it behaves just like a USB drive with a tiny amount of storage. In its folder, is a web page. You open the webpage in your browser, and there’s only one instruction to follow: “Drop a file onto the drive”. Once you do that, the OpenDime automagically generates a unique address for you to receive Bitcoin with.

[https://opendime.com Opendime.com]

* [https://opendime.com/#faq Opendime FAQ]
* You can watch a [https://www.youtube.com/watch?v=9UFF9d3Y1BY video here]
* Read this [https://medium.com/@beautyon_/exquisite-opendime-ad1195a2790e review]
* Multi-language user interface: 中文 • 日本語 • English • Portuguese • Français • Deutsch • Русский
* Works as USB drive with no need for software
* [https://github.com/opendime/electrum Opendime Electrum plugin]
* [https://github.com/opendime/ Opendime source files and key verification]

 

=== Coldcard: Ultra-secure Bitcoin Hardware Wallet ===

[[file:Coldcard.png|300px|thumb|left|Coldcard Front and Back]]

* Coldcard is an easy to use, ultra-secure, open-source and affordable hardware wallet that is easy to back up via an encrypted microSD card. Your private key is stored in a dedicated security chip. MicroPython software design allows you to make changes.
* BIP39 based, which means you can backup the secret words onto paper, and have lots of sub-accounts and unlimited independent payment addresses. Now with BIP39 passphrase support, unlocking up to 5.9e197 additional wallets from the same seed words! It knows how to understand transactions, so you can see what you are approving.
* The first "Partially Signed Bitcoin Transaction Format" - PSBT (BIP 174) native wallet which can be used completely offline for its entire lifecycle. See HWI for Bitcoin Core support!
* True air-gap cold operation via MicroSD sneakernet or standard via USB

Warning: Coldcard Mk2 and Mk3 have a random number generation flaw which allows for funds to be drained. Other models are also affected to a lesser degree. [https://blog.coinkite.com/coldcard-mk3-seed-generation-warning/ View the full advisory here]

[http://www.coldcardwallet.com Coldcardwallet.com]

* [https://coldcardwallet.com/faq Coldcard FAQ]
* [https://coldcardwallet.com/docs Coldcard Docs]
* [https://github.com/coldcard/firmware Coldcard Source Code]

 

=== CoolWallet: The Ultimate Bitcoin Safe ===


[[File:CoolWallet in the box.jpeg|300px|thumb|left|CoolWallet showing Launch App, waiting for user to connect with smartphone via Bluetooth]]

CoolWallet is a credit card sized Bluetooth device that stores and secures your bitcoins and private keys. It fits in your wallet and works wirelessly.

Every Bitcoin transaction must be manually confirmed and approved through its e-paper display and button.

CoolWallet only acknowledges the paired smartphone. Whoever stole the CoolWallet are not able to steal any bitcoins. Using recovery Seed can restore all your bitcoins in case you lost the device.

[https://coolbitx.com coolbitx.com] | [https://github.com/CoolBitX-Technology/coolwallet-ios Source and specifications]

 

=== BlochsTech card: Your user friendly Bitcoin wallet ===


[[file:BlochsTech Bitcoin card hardware wallet.jpg|300px|thumb|left|Graphic printed on front of BlochsTech cards.]]

The BlochsTech open Bitcoin card is an open protocol secure hardware Bitcoin wallet your grandmother could use.
For shops it's faster to accept than slow QR code based wallets and more reliable as it works offline.

Currently it's of course in a novelty phase like Casascius coins (of which thousands were sold),
however in the long run it is fully capable of functionally replacing the VISA system in all nations.

[http://www.BlochsTech.com BlochsTech.com]

 

=== BitLox Bitcoin Hardware Wallet ===
[[file:Bitlox.jpg|300px|thumb|left|BitLox Bitcoin Hardware Wallet]]

BitLox is a metal cased (aluminum or titanium) bitcoin hardware wallet that works with their own web based wallet by USB and apps for iPhone and Android using Bluetooth LE.

At present it is the only bitcoin hardware wallet you can buy that works with iPhone. The device weighs one ounce and is the size of a credit card 4 mm thick.

Bitlox allows you to set up hidden wallets. Unlike other hardware wallets your seed is never displayed on a connected computer or phone but only on the Bitlox. All your wallet, device and transaction PINs are only entered on the BitLox and never on any app.

BitLox has also implemented several advanced security features not available on any other bitcoin hardware wallet.

[http://www.bitlox.com bitlox.com]

 

=== Ledger Nano S ===
[[File:ledger_wallet_nanos_photo.png|300px|thumb|left|Ledger Wallet Nano S]]

Ledger Nano S is a secure Bitcoin hardware wallet. It connects to any computer through USB and embeds a built-in OLED display to double-check and confirm each transaction with a single tap on its buttons. It is architectured around a Secure Element (ST31 family) and built on top of the BOLOS platform, a powerful and flexible Operating System allowing the secure execution of multiple Open Source applications in full isolation.

Main features:
* cryptographic secrets protected by a secure chip
* open source embedded Bitcoin app
* Confirmation of transactions on the embedded screen
* Built-in 4 digits PIN security lock
* Built-in onboarding (seed generation and recovery)
* BIP39 seed (12/18/24 words), easy backup and restoration
* Multi-apps support: FIDO U2F, GPG, SSH…
* USB connectivity
* Foldable and compact casing

[https://www.ledgerwallet.com/products/12-ledger-nano-s Ledger Nano S product page]

 

=== Ledger Nano X ===

[[File:Ledger Nano X.png|300px|thumb|left|Ledger Wallet Nano X]]
Ledger Nano X is a secure hardware wallet. It features Bluetooth Low Energy (BLE) connectivity enabling it to be used with Android or iOS devices without the need of a cable. 
Main features:
* Multi-services: Hardware Wallet, Cryptographic Platform, Password Manager, Second Factor authenticator
(FIDO)
* Comply with several cryptocurrencies
* USB connectivity
* BLE v5.0 connectivity
* Open Source Device App: all Device Apps developed by Ledger can be reviewed and verified by End-Users
* Developer friendly: develop a Device App and then install it on the Ledger Nano X
* Comply with the main BIP standards: [BIP32], [BIP39] and [BIP44]
* Multi-platform: Windows (7+), Mac (10.9+), Linux or Chrome OS
* OLED screen: to verify the transaction data (amount, address)
* Buttons: used to get the End-User’s consent relative to sensitive operations like unlocking the device or processing a transaction
* PIN: to unlock the Ledger Nano X
* Plausible deniability: an additional PIN linked to a passphrase can be defined to create an hidden account
* Genuine PSD: cryptographic attestation mechanisms ensuring that the Ledger Nano X is a genuine one
* Post-issuance capability: all piece of software (MCU Firmware, SE Firmware, Device Apps) can be securely updated

[https://shop.ledger.com/products/ledger-nano-x Ledger Nano X product page]

 

=== [[Cypherock Wallet]] ===
[[File:Cypherock x1 wallet.png|500px|thumb|left|Cypherock X1 Wallet]]

[[Cypherock Wallet]] is a secure Bitcoin hardware wallet that does not require a manual seed phrase backup.

Cypherock X1 uses [[Shamir Secret Sharing]] to break the master seed into 5 Cryptographic parts further stored on 5 tamper-proof hardware components - namely the X1 vault and 4 X1 cards. Each of these 5 components can have an optional PIN set by the user as an additional layer of security. These hardware components interact with each other using NFC technology. Using a 2-of-5 threshold scheme, any 2 of the 5 parts can be used to reconstruct the private key and make transactions.

Additional Features:
* Audited by KeyLabs, a hardware security firm that has found vulnerabilities in Ledger and Trezor before.
* It is [https://www.github.com/cypherock open-source] and has been scrutinized, and certified ‘reproducible’ by [https://walletscrutiny.com/hardware/cypherockx1 WalletScrutiny].
* USB connectivity
* OLED screen: to verify the transaction data (amount, address)
* Comply with the main BIP standards: [BIP32], [BIP39] and [BIP44]
* Multi-platform: Windows (7+), Mac (10.9+), Linux or Chrome OS
* 5-way joystick: used to get the End-User’s consent for sensitive operations like processing a transaction
* You can also use the Cypherock X1 as a [https://www.cypherock.com/wallet-backup seed phrase backup manager] since it allows the user to secure multiple seed phrases inside the same product.
* It is soon going to come with an inheritance service that allows a user to setup an inheritance of the assets without compromising privacy and control of the assets

[https://www.cypherock.com Cypherock Website] | [https://www.cypherock.com/product/cypherock-x1 Cypherock Shop] | [https://www.cypherock.com/security Cypherock X1 docs] | [[Cypherock Wallet|Cypherock Wiki]]

 

=== [[Prokey|Prokey Optimum Trezor clone]] ===
[[File:Optimum-in-hand.jpg|300px|thumb|left|WebUSB-enabled hardware wallet, the Prokey Optimum]]
The Prokey Optimum is a [[Trezor|Trezor One clone]] that connects to any computer and android phones through USB and users required to always press OK button on device to confirm right addresses, amounts, and fees before making any transactions.
It focuses on the following features :

* Secure Firmware: Genuine firmware that implements mutual authentication between the device and the server to prevents supply-chain attacks.
* All-Inclusivity: No third-party wallets, manage everything on a single platform
* Supports Bitcoin, Ethereum, ERC20 Tokens, OMNI Layer and more cryptocurrencies, It's the first hardware wallet that fully support USDT as both Omni and ERC20 Tokens
* In-Browser Operation: WebUSB-based operations renders no need of additional download of bridges, applications, extensions, or executable files

Equipped with other features like passphrases and offline recovery seed checking, the Prokey Optimum offers maximum security and also is user-friendly to provide the best experience when dealing with cryptocurrency.

[https://prokey.io/ Homepage of Prokey Hardware Wallet]

 

=== Secalot ===
[[File:secalot_wallet.png|300px|thumb|left|Secalot]]

Main features:
* Software and hardware are fully open sourced.
* Utilizes a secure microcontroller with a high performance dedicated cryptographic co-processor.
* Integrates with the popular Electrum wallet.
* PIN-code protected.
* Confirm transactions with a touch button press on the device.
* Supports P2PKH, P2SH, and segWit transactions.
* Updatable firmware.
* Extra functionality: OpenPGP smart card, FIDO U2F authenticator, one-time password generator.

Website: [https://www.secalot.com www.secalot.com]

 

=== ELLIPAL - Airgapped hardware wallet with mobile support ===
[[File:Ellipal wallet.png|300px|thumb|left|ELLIPAL]]

ELLIPAL hardware wallet secures keys in cold storage without connections except for LCD screen. It works with companion mobile App via QR code.

Main features:
* Working with mobile phone via QR code
* Internet Isolated Cold Wallet
* Supporting multi-currencies and more than 7,000 tokens
* Supports P2PKH, P2SH, and segWit transactions
* 4" Screen with touch panel
* Support private key import
* PIN-code and gesture pattern protect
* Confirmation of transactions details on the screen
* BIP32/BIP39/BIP44
* iPhone and Android companion App: account management, market info and coin exchange.

[https://www.ellipal.com ELLIPAL Hardware Wallet Homepage] | [https://www.ellipal.com/pages/coin-list ELLIPAL Supported Coins]

 

=== ELLIPAL Titan Cold Wallet ===
[[File:Ellipaltitan.jpg|300px|thumb|left|ELLIPAL Titan]]

ELLIPAL Titan is the upgraded version of the ELLIPAL EC01 hardware wallet. Main upgrades are within the hardware which improves protection against physical attacks while keeping absolute protection against remote attacks. ELLIPAL Titan works with ELLIPAL mobile App to secure and manage your cryptocurrency. Information is transferred between the cold wallet and App via QR code only.

New additional features:
* IP65 metal sealed frame - Light water jet & dust protection
* Disassembly test: [https://www.youtube.com/watch?v=DuPcJudtd2o Video]
* Fully isolated components, can never be connected to another device
* USB port removed - no ports on the device
* Anti-Tamper feature - data automatically deleted upon detection of a breach
* Decentralized Finance: [https://www.ellipal.com/pages/buy-crypto buy cryptocurrency], exchange, and stake of coins.
* Verifiable and secure QR code [https://github.com/ELLIPAL?tab=repositories Github]

[https://www.ellipal.com/pages/coldwallet Buy Cold Wallet] | [https://www.reddit.com/r/ELLIPAL_Official/ ELLIPAL on Reddit] | [https://www.ellipal.com/pages/reviews ELLIPAL Reviews]

 

=== [[Trezor|Trezor Model T]] ===
[[File:Trezor-model-t-photo-front.jpg|300px|thumb|left|Trezor Model T]]

Trezor Model T is the premium version and next-generation cryptocurrency hardware wallet. In addition to the functionalities of Trezor One, it has a colored touchscreen for secure on-device input, modern design, an SD card slot, and some other more advanced features.
For more information see [https://wiki.trezor.io/Trezor_Model_T Trezor Model T] and this [https://trezor.io/#comparison comparison table]

[https://shop.trezor.io Trezor E-shop] | [https://wiki.trezor.io Trezor Wiki] | [https://trezor.io Trezor Homepage]

 

=== D'CENT Biometric Wallet - BLE enabled Hardware Wallet ===
[[File:DCENT_Biometric_Wallet.png|300px|thumb|left|D'CENT Biometric Wallet]]

D'CENT Biometric Wallet is a secure multi-cryptocurrency hardware wallet. It connects by using Bluetooth or USB to any mobile devices. The wallet is based on multi-IC architecture built on Secure Element(EAL5+) embedded with the SecureOS to provide robust security for the secure execution of multiple wallet applications.

Main features:
* Cryptographic secrets protected by a secure chip
* Large OLED (128x128) display for confirmation of transactions and QR Code for P2P transactions
* Built-in biometric sensor for authentication and also supports the PIN
* Built-in onboarding (seed and key generation in Secure Element)
* BIP39 seed (24 words), easy backup and recovery
* Easy and convenient FW update (no recovery is required after update)
* Bluetooth and USB connectivity

[https://dcentwallet.com D'CENT Wallet Homepage] | [https://medium.com/dcentwallet D'CENT on Medium] | [https://www.youtube.com/channel/UCKnYqiM3g3iaaAKcRZf-kbA D'CENT Youtube]

 

=== Keystone Wallet - Air-gapped with QR code and Secure Element ===
[[File:Vault_pro.png|300px|thumb|left|Keystone Wallet Essential/Pro]]

[[Keystone]] Wallet is a completely air-gapped hardware wallet that uses verifiable QR codes to transmit transaction information back and forth with a mobile app. It houses an FIPS 140-2 Secure Element that uses four superimposed physical sources for true random number generation (TRNG). Private keys never leave the Secure Element when transactions are signed. Keystone Wallet’s innovative Web Authentication process helps prevent supply chain attacks through double asymmetric encryption implementing our backend HSM server. Keystone Wallet’s Secure Element’s BIP 32, 39, and 44 compliant firmware is open source ([https://github.com/keystonejs/keystone Github]).

Keystone Wallet Essential & Pro Features:
* Air-gapped through auditable QR code data transmissions
* Secure Element physical entropy private key generation and side-channel attack prevention
* Open source Secure Element firmware (industry first)
* Detachable battery (industry first)
* MicroSD firmware upgrading
* 4-inch touchscreen
* AAA battery support to prevent battery failure
* Bitcon-only firmware version compatibility
* Better camera for smoother QR code transactions

Keystone Wallet Pro Features:
* Fingerprint sensor for device unlock and transaction signing
* Upgraded self-destruct mechanism
* Rechargeable battery

[https://keyst.one/ Keystone Wallet Homepage] | [https://blog.keyst.one/ Keystone Wallet on Medium] | [https://shop.keyst.one/products/keystone-pro Keystone Wallet Shop]

 

=== BitBox02: Swiss made open source ===
[[File:BitBox02.png.jpg|300px|thumb|left|BitBox02]]

The BitBox02 hardware wallet equips individuals to easily store, protect and transact in Bitcoin. Its companion, the BitBoxApp, provides an all-in-one solution to securely manage your coins.

Simple and secure, a good starting point for beginners:
* Create your wallet in minutes via the setup wizardInstant backup to the included microSD card
* In-app guide that answers common questions
* A bright OLED screen and intuitive touch sensors to securely verify and confirm transactions
* The USB-C connector works with your computer or Android smartphone (adapter and extension cable included)

Many advanced features for expert users:
* Easy connection to your own Bitcoin full node
* Secure multi-signature with account registration directly on the device
* Backup to microSD card with additional option to export the BIP39 recovery words
* Granular coin control for Bitcoin UTXO
* Reproducible builds of firmware to make sure binary releases actually run the open-source code
* Supported by Electrum and wallets using HWI

Secure hardware made in Switzerland:
* Software and hardware are open-source and can be independently audited
* Secure dual-chip architecture allows usage of a secure chip for physical device hardening
* Bitcoin-only edition features focused firmware with less attack surface
* Very discreet due to its small form factor and no visible screen when powered off
* BitBox hardware wallets have been available since 2016
* Engineered and manufactured in Switzerland

[https://shiftcrypto.ch/bitbox02 BitBox02 product page] | [https://github.com/digitalbitbox Source code]

 

=== Frostsnap ===
[[File:Frostsnap Hardware Wallet.png|200px|thumb|left|Frostsnap devices daisy-chained into a mobile phone. Choosing a threshold for the multisignature wallet.]]

Frostsnap hardware wallets make [[multisignature]] security simple. Each wallet consists of a set of Frostsnap devices and a chosen threshold (e.g. 2-of-3). The wallet's key is created through distributed key generation and never exists on any one device; transactions are signed using [https://eprint.iacr.org/2020/852 FROST], so only a threshold of devices cooperating can produce a signature.

Frostsnap's multisignature is enforced through mathematics rather than [[Script|Bitcoin script]]. Transactions are signed with an ordinary [[Schnorr]] signature spending a [[Taproot]] key path. With a single group public key, Frostsnap wallets are indistinguishable on-chain from single-signature Taproot wallets, paying single-signature fees and revealing nothing about the signing policy.

Main features:
* Recovery needs only a threshold of devices or backups, with no descriptor metadata to back up
* No individual device is trusted: the phone verifiably contributes entropy to key generation and signing, protecting against weak randomness, supply chain attacks, and devices leaking secrets through their signatures (see [[Hardware wallet#Security risks|Security risks]])
* Losing a device below the threshold loses nothing; stealing a device below the threshold gains nothing
* No PINs or passphrases to complicate recovery or inheritance
* No vendor lock-in: a threshold of backups reconstructs a key spendable without Frostsnap hardware or software
* Touchscreen, USB-C, aluminium casing; app for Android, Linux, macOS and Windows
* Fully open source (MIT), written in [https://www.rust-lang.org Rust], with reproducible firmware builds

[https://frostsnap.com frostsnap.com] | [https://frostsnap.com/technical Technical documentation] | [https://github.com/frostsnap/frostsnap Source code]

 

== Not purchasable hardware wallets ==

=== Ledger HW.1 - USB Smartcard Hardware Wallet ===
[[File:Btchip_dongle.jpg|220px|thumb|left|HW.1 inserted in a laptop]]

HW.1 is an implementation of a deterministic ([[BIP 0032]]) Hardware Wallet on a USB smartcard.

It is typically used as a blind secure device for multi signature transactions - holding a set of derived private keys and signing transactions without requiring user confirmation.

Power users can rely on it to confirm all transactions with a second factor scheme turning the dongle into a keyboard typing what the user is supposed to have signed, as a protection against malware.

It is also possible to customize HW.1 for more specific needs, such as creating a prepaid card without revealing the deterministic seed before it is received by the user, or securing bitcoin transactions on a server.

[https://www.ledgerwallet.com/products/3-ledger-hw-1 E-shop] | [https://ledgerhq.github.io/btchip-doc/bitcoin-technical.html Technical Documentation]

 

=== Ledger Nano - USB Smartcard Hardware Wallet ===
[[File:ledger_wallet_photo.jpg|300px|thumb|left|Ledger Wallet USB]]

Ledger Nano protects your Bitcoin data within a smartcard. Its micro-processor certified against all types of attacks (both physical and logical), and has been used in the banking industry for decades (think credit card chips). The device connects to your computer through the USB port and will do all the Bitcoin cryptographic heavy lifting such as signing transactions inside its secure environment. You can therefore use your Bitcoin account with maximum trust, even on an insecure or compromised computer.

The second factor verification of the transaction signature can be done either with a paired smartphone (Android, iOS) or a physical security card.

The Ledger Wallet Chrome application (available also on Chromium) provides an easy onboarding as well as a seamless user experience, and the Nano is compatible with numerous third party software: [[Electrum]], [[Mycelium]], [[GreenAddress]], Greenbits, [[Coinkite]] and Copay.

[https://www.ledgerwallet.com/products/1-ledger-nano Ledger Nano product page] | [https://github.com/LedgerHQ Source and specifications]

 

=== Ledger Unplugged - NFC Smartcard Hardware Wallet ===
[[File:ledger_unplugged_photo.jpg|300px|thumb|left|Ledger Unplugged NFC]]

The Ledger Unplugged is a credit card sized NFC hardware wallet. It embeds an open source Java Card app and is compatible with all NFC enabled Android phones.

The device can be used with Mycelium or Greenbits. In case of loss, you can restore it on any Ledger Wallet (Nano or another one) or all other compatible solutions (BIP 39).

[https://www.ledgerwallet.com/products/6-ledger-unplugged Ledger Unplugged product page] | [https://github.com/LedgerHQ/ledger-javacard Source code]

 

=== BWALLET TREZOR clone ===

[[File:BWALLET_Trezor_Clone.jpeg|200px|thumb|left|Chinese clone of Trezor]]

BWALLET is a clone of Trezor by a Chinese company.
Trezor code is open source and this device operates like a Trezor.
However, this product has been [https://www.reddit.com/r/Bitcoin/comments/2tyier/bwallet_review_by_trezor_developer/ reviewed by Marek aka Slush(Trezor developer)] and he has found some problems which makes this device less than 100% compatible, for example it doesn't work with [http://mytrezor.com myTREZOR.com] website and it does not work with Trezor official firmware.

[http://mybwallet.com MyBWALLET.com] | [http://www.bidingxing.com/en/bwallet Buy BWALLET]

 

=== Pi Wallet - cold storage ===
[[File:Piwallet.jpeg|300px|thumb|left|Pi-Wallet]]

The Pi-Wallet is a small computer with the [[Armory]] bitcoin client.

Transactions are signed offline, then transferred on a USB stick via [https://en.wikipedia.org/wiki/Sneakernet Sneakernet] to an online system for broadcasting.

[https://www.pi-wallet.com/ pi-wallet.com]

 

=== BitcoinCard Megion Technologies-Card based wallet ===
[[File:Bitcoincard-medley-large.jpg|400px|thumb|left|Bitcoin Card]]
[http://www.bitcoincard.org/ Bitcoincard Home Page]

[http://blog.bitinstant.com/blog/2012/6/19/our-discovery-in-vienna-the-bitcoin-card.html Excellent review by evoorhees]

Incorporates a e-paper display, keypad, and radio (custom ISM band protocol.) Unfortunately it is fairly limited in terms of transaction I/O, requiring a radio gateway or another bitcoincard wherever funds need to be transferred.

 

=== BitSafe - allten/someone42's hardware wallet ===
[[File:Bitsafe-wallet-sizecompare.jpg|200px|thumb|left|Bitsafe wallet]]
[https://bitcointalk.org/index.php?topic=152517.0 Final BitSafe announcement]

Signing transactions only, requires USB host software for transactions & USB power. Has a OLED display and Confirm/Cancel buttons. Evolved out of someone42's prototype below, and has significant contributions from someone42 as well.
 

=== Swiss Bank in Your Pocket - Hardware wallet ===
[[File:SBIYP.png|300px|thumb|left|Swiss Bank In Your Pocket]]

The Swiss Bank in Your Pocket is a Windows Desktop Application providing functionality for 5 Bitcoin Wallets and a Bitcoin Vault.

The Bitcoin Vault can only send Bitcoins to the Bitcoin Wallets with in the application. Each Bitcoin wallet can have up to 5 Receive addresses. The intuitive user interface is designed for ease of use. USB security key is required to make any type of transaction. frontend software is installed on windows. Package includes secure USB key, and an additional recovery USB key. So in case of an accident, customer will have an additional backup to access their wallets.

[https://swissbankinyourpocket.com/ swissbankinyourpocket.com]

 

=== BitBox 01 (Digital Bitbox) ===
[[file:Digital-bitbox.png|thumb|left|Digital Bitbox Hardware Wallet]]

* Secure hardware RNG & key storage using [http://www.atmel.com/Images/Atmel-8914-CryptoAuth-ATAES132A-Datasheet.pdf crypto element] with 50 year lifespan and an epoxy-filled case.
* Offline backup and recovery of [[BIP_0032|BIP-32]] seed with a micro SD card rather than [[BIP_0039|BIP-39]] phrase written on paper as in Trezor.
* Native software wallet client and ability to use a mobile phone for 2FA and to verify transaction details.
* Multisig out-of-the-box including Copay support.
* [https://github.com/digitalbitbox Open Source] ([https://github.com/digitalbitbox/mcu#digital-bitbox-firmware firmware], [https://github.com/digitalbitbox/mcu/blob/bf48984fd4a47d9ebf6814f7d01b078964587c7c/src/bootloader.c bootloader], [https://github.com/digitalbitbox/dbb-app desktop client]).
* Full FIDO U2F support (https://en.wikipedia.org/wiki/Universal_2nd_Factor)
* Made in Switzerland (a country with strong privacy laws) by [[Bitcoin Core]] developer Jonas Schnelli.

[https://digitalbitbox.com digitalbitbox.com]

 

=== someone42's original prototype ===
[[File:Someone42-wallet-prototype.jpg|300px|thumb|left|someone42's original prototype]]
[https://bitcointalk.org/index.php?topic=78614.0 Hardware Bitcoin wallet - a minimal Bitcoin wallet for embedded devices]

Signing transactions only, requires USB host software for transactions & USB power. All work is rolled into the above BitSafe wallet currently.
 
=== Other/Defunct but with good discussion: ===
* natman3400's BitClip Jun 2011 [https://bitcointalk.org/index.php?topic=24852.0 https://bitcointalk.org/index.php?topic=24852.0]
:Seems to have gone defunct around Dec 2011. Some good ideas though and seemed to have started on execution.
* jim618 hardware wallet proposal Apr 2012 [https://bitcointalk.org/index.php?topic=77553.0 Dedicated bitcoin devices - dealing with untrusted networks]
:Great discussion and good ideas from jim618. Also linked the following video:
* Prof. Clemens Cap's hardware wallet? (video:)[https://www.youtube.com/watch?v=IavQ-Wc8S1U Clemens Cap about electronic bitcoin wallet at EuroBit]
:Clemens Cap of Uni Rostock explains the Electronic Bitcoin wallet device he's working on. It's based on adafruit microtouch device.
* ripper234's discussion based on Yubikeys Aug 2012 [https://bitcointalk.org/index.php?topic=99492 Having a YUBIKEY as one of the parties for m-of-n signatures]
:The use of Yubikeys. They only support symmetric crypto, so you'd have to trust the host device.
* kalleguld's hardware wallet proposal Oct 2012 [https://bitcointalk.org/index.php?topic=115294.0 Proposal: Hardware wallet (Win 3 BTC)]
* Vaporware: Matthew N Wright's ellet [https://bitcointalk.org/index.php?topic=85931.0 ANN The world's first handheld Bitcoin device, the Ellet!] (Vaporware)

== Smart Card based wallets ==
This type of device requires complete trust in the host device, as there is no method for user input.
See [[Smart card wallet]]

== Related Resources ==
* [https://bitcoinnewsmagazine.com/best-bitcoin-hardware-wallet-2015/ Best Bitcoin Hardware Wallet 2015] - reviews of all bitcoin hardware wallets.
* [http://99bitcoins.com/trezor-vs-ledger-hands-hardware-wallets-review/ TREZOR vs. Ledger] - User reviews and Reddit feedback
* [https://bitcointalk.org/index.php?topic=125383.0 Hardware wallet wire protocol]: slush's Hardware wallet wire protocol discussion
* [https://bitcointalk.org/index.php?topic=19080.msg272348#msg272348 Re: Split private keys]: kjj's Todo List discussion for client protocol requirements
* [https://bitcointalk.org/index.php?topic=134277.0 Hardware Wallet Roundup]
* [https://www.buybitcoinworldwide.com/wallets/ Bitcoin Hardware Wallet Comparison] - information about using Bitcoin hardware wallets for cold storage.
* [https://www.weusecoins.com/bitcoin-ledger-wallet-review/ Ledger Wallet Review]

== See Also ==

* [[Storing bitcoins]]
* [[How to set up a secure offline savings wallet]]
* [[Cold storage]]

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

Ams

2026-07-22T08:10:11Z

NotATether: Expand page

'''Avalon Management System''' ('''AMS''') is an open-source toolset for managing farms of Avalon [[Mining|Bitcoin miners]]. It was published by Canaan Creative and consists of server and web-client components.

The project's repository describes AMS as "A toolset to manage BTC Farm" and documents installation, configuration and the addition of Avalon miners by network address.<ref name="repository">{{cite web|url=https://github.com/Canaan-Creative/Avalon-Management-System|title=Avalon Management System|publisher=Canaan Creative on GitHub|accessdate=20 July 2026}}</ref> GitHub lists four releases; the latest shown is the development release <code>v3.0.0-dev7</code>, dated 25 December 2017.<ref name="repository" />

==External links==
* [https://github.com/Canaan-Creative/Avalon-Management-System Source code]

==References==
<references />

[[Category:Mining software]]

AltoCenter

2026-07-20T08:49:20Z

NotATether: Altocenter is not working anymore

{{infobox company
|name=AltoCenter
|industry=[[Exchange]]
|website=https://altocenter.com/ (defunct)
}}

'''AltoCenter''' was a centralized cryptocurrency exchange that advertised trading in [[Bitcoin]] and other digital currencies against US dollars, euros and Chinese yuan. A 2015 announcement supplied by the company identified AltoCenter with an address in Panama City, Panama.<ref name="announcement">{{cite web|url=https://www.accessnewswire.com/425829/free-bitcoin-debit-card-offered-by-altocenter-bitcoin-and-litecoin-exchange|title=Free Bitcoin Debit Card Offered by AltoCenter Bitcoin and Litecoin Exchange|publisher=ACCESS Newswire|date=11 February 2015|accessdate=20 July 2026}}</ref>

==Feautres==
The February 2015 announcement described a web-based trading platform for Bitcoin, Litecoin and other digital currencies. It advertised deposits and withdrawals using cryptocurrencies and Perfect Money, as well as bank wires, SEPA payments in Europe and optional debit cards.<ref name="announcement" />

The announcement stated that Perfect Money deposits were instant, cryptocurrency deposits could take up to an hour to appear and bank transfers could take two to five working days.<ref name="announcement" />

==Status==
AltoCenter is no longer operating at its former domain, which appears to be listed for sale as of 2026.<ref>{{cite web|url=https://altocenter.com/|title=altocenter.com domain listing|publisher=GoDaddy|accessdate=20 July 2026}}</ref> The current ownership of the domain should not be assumed to be connected with the former exchange.

==See also==
* [[Buying bitcoins]]
* [[Selling bitcoins]]
* [[Currency exchange]]

==External links==
* [https://altocenter.com/ Former AltoCenter domain]

==References==
<references />

[[Category:Defunct exchanges]]
[[Category:Historical services]]

Alternative chain

2026-07-20T08:41:13Z

NotATether: No need to make parent bold

An '''alternative chain''' is a system using the block chain algorithm to achieve distributed consensus on a particular topic. Alternative chains may share miners with a parent network such as Bitcoin's; this is called '''merged mining'''. The digital currencies of alternative chains are commonly called alternative currencies, or '''altcoins''' for short.

Alternative chains have been suggested as ways to implement [http://www.dot-bit.org DNS], [[Bitcoin OTC|P2P currency exchanges]], SSL certificate authorities, timestamping, file storage and voting systems.

== Context ==

The term ''alternative chain'' is used narrowly in the original sections below for an independent Bitcoin-style proof-of-work chain, particularly one that can share work with Bitcoin miners. The design grew out of early discussions such as the BitcoinTalk thread "BitDNS and Generalizing Bitcoin", where participants considered separate blockchains for decentralized DNS and other applications.<ref name="bitdns">{{cite btct|id=1790|title=BitDNS and Generalizing Bitcoin|date=15 November 2010}}</ref>

[[Namecoin]] became the best-known early implementation of this idea. Its project describes Namecoin as a Bitcoin-based key/value registration and transfer system for DNS, identities and other internet-infrastructure uses, and says it was the first fork of Bitcoin and the first system to implement merged mining and decentralized DNS.<ref name="namecoin">{{cite web|url=https://www.namecoin.org/|title=Namecoin|publisher=Namecoin|accessdate=20 July 2026}}</ref>

Modern usage is broader. An independent blockchain need not copy Bitcoin's transaction model, proof-of-work consensus, block format or mining system. The following families overlap; they describe different execution, consensus and governance choices rather than mutually exclusive categories.

== Objective ==

Bitcoin uses the [[block chain]] algorithm to achieve distributed consensus on who owns what coins. Block chains were invented specifically for the Bitcoin project but they can be applied anywhere a distributed consensus needs to be established in the presence of malicious or untrustworthy actors.

Whilst it's possible to abuse the Bitcoin financial block chain for other purposes, it's better to set up an alternative network and chain which share the same miners. There are several reasons to do this.

* The block chain is a large, complex data structure shared between many people. Verifying its integrity requires many slow (and thus expensive) operations like ECDSA verifications and disk seeks. Everyone who takes part in Bitcoin today runs a node and thus maintains the whole thing. Whilst in future end-users will probably use more efficient but slightly less secure modes (SPV), merchants and miners will probably always pay the full costs for the upkeep of this shared data structure. All these people today are united by a common interest in a new form of payments. They may or may not also be interested in other schemes. So one reason to keep the Bitcoin chain for finance is it's unfair to externalize the costs of unrelated schemes onto people who are interested only in payments - the canonical example being merchants. Increasing the cost of accepting Bitcoins for goods and services hurts everyone who uses the system by reducing the number of merchants or increasing their costs.

* Another reason is that it's just bad engineering to cram every possible distributed quorum into the design constraints of Bitcoin. The transaction format Bitcoin uses is flexible but ultimately designed for finance. You cannot leave out the "value" field. It's always there, even if it'd make no sense for your particular application. Building non-financial applications on top of a financial system results in bizarre protocols and code that are difficult to understand, leading to maintainability problems.

* One final reason is that [[Satoshi Nakamoto|Satoshi]] was opposed to putting non-Bitcoin related data into the main chain. As creator of the system, his opinion should carry a lot of weight with anyone serious about extending it.

=== Designing a new network ===

To create a new network that uses Nakamoto block chains, you need to start by defining what a transaction in your new network means. Bitcoin transactions split and combine value using scripts, but yours don't have to do that. They could be anything. Here's an example of a simple DNS style "transaction" described using [http://code.google.com/p/protobuf/ Google protocol buffers] syntax.

message NameTx {
required string name = 1;
repeated bytes ip_addresses = 2;
required bytes pubkey = 3;
enum ClaimType {
NEW_NAME,
TRANSFER
}
required ClaimType type = 4;

// Only used if type == TRANSFER. The new owner of the name and signature proving current ownership.
optional bytes dest_pubkey = 5;
optional bytes signature = 6;
}

This is very different to a Bitcoin style transaction. There's no concept of inputs, outputs, addresses, values or scripts. It's got what you need for a very simple DNS style scheme (that lacks abuse controls etc) and nothing more. There's also no concept of a "coinbase" transaction.

The block definition is also up to you. It does not have to be formatted in the same way as Satoshi chose, but you need most of the same conceptual parts. You also need to store something else, some data from Bitcoin. Here's a minimal example of what's needed:

message MyBlock {
required bytes prev_block_hash = 1;
required uint32 difficulty = 2;
required uint32 time = 3;

repeated MyTx transactions = 4;
}

message SuperBlock {
required MyBlock my_data = 1;
required BitcoinData bitcoin_data = 2;
}

It's important to observe what we don't have as well as what we do. We don't have the following fields from Satoshis format:

# version: protobufs handles the versioning of binary data formats for us
# merkle root: you can choose to arrange your transactions into a merkle root if you like, so you can use the same disk space reclamation trick Satoshi did. But it's strictly optional. If you want to simplify things down you can skip it.
# nonce

== Sharing work ==

The bitcoin_data field is how you share work with miners today (assuming they opt in by installing your software alongside their bitcoin node). It's defined like this:

message BitcoinData {
// A Bitcoin format block header. Because it's in Satoshis custom format we represent this as a byte array.
required bytes header = 1;

// The first transaction from the block.
required bytes coinbase_tx = 2;

// The merkle branch linking the coinbase transaction to the header.
required bytes coinbase_merkle_branch = 3;

// The coinbase scriptSig contains bits of data in order. Which one is our hash?
required int coinbase_tx_index = 4;
}

All you need to share work is the above four things.

A [[wikipedia:Merkle tree|merkle tree]] is a data structure in which each node in the tree is a hash. The leaf nodes are hashes of the things you want to include in the tree. The interior nodes are hashes of the concatenations of the child nodes. A merkle branch is a part of a merkle tree which allows you to cryptographically prove that something you're given was in the tree, without needing everything that was in the tree. They are calculated by the CBlock::GetMerkleBranch() function in the Bitcoin code.

We store a merkle branch here for efficiency. It means no matter how large the current Bitcoin block is, your alternative network only needs to handle a small amount of data. You could just store the entire Bitcoin block - that would be simpler but inefficient.

The merkle branch links the coinbase transaction to the block header, so you can prove it was in that block. The coinbase TX is a regular Bitcoin coinbase (that makes new coins and claims fees), except the scriptSig on its input contains an extra entry that todays scriptSigs don't. That extra entry is a hash of your block structure. The coinbase scriptSig today is formatted like this:

void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce, int64& nPrevTime)
{
.....
pblock->vtx[0].vin[0].scriptSig = CScript() << pblock->nBits << CBigNum(nExtraNonce);
.....
}

Just the difficulty bits and the "extra nonce". But it's actually allowed to contain anything, as long as it's not too big. So in your new blocks it'd be:

<MyBlock hash> <nBits> <nExtraNonce>

To get the MyBlock hash into Bitcoin requires a presently unimplemented RPC command, "setextrahashes". It'd update a global list and the IncrementExtraNonce function would include the extra hashes when the scriptSig is built. This is a very simple change to Bitcoin.

In the scriptSig above the coinbase_tx_index would be zero. It's possible to work on an arbitrary number of alternative chains simultaneously:

<MyBlock hash> <SomeOtherChainBlock hash> <nBits> <nExtraNonce>

in which case the BitcoinData message for SomeOtherChain would be 1 rather than zero.

A more complex change is the other new RPC. Because you have your own chain, it has its own difficulty. Most likely it'll be different to Bitcoins own. So you need a way to tell Bitcoin "when you find a block that matches an extradifficulty, please let me know". To mine on multiple difficulties at once, the node vends work (via getwork) matching the easiest difficulty. When a miner reports finding a solution the difficulty is checked to see which chains it is sufficiently difficult for.

Important note: Your chain has its own difficulty and as such the block creation rate is independent of how much mining takes place.

== Independent node software ==

Your new network has its own codebase. It can be written in whatever language you like, use whatever P2P protocol you like, store its data however you like and so on.

When a node on your network receives a message informing it about a new transaction, it verifies that transaction follows the rules of your network. To use our simple DNS example it would verify that if you're claiming a new name, it doesn't already exist and if you're transferring a name that the signatures are correct.

If the transaction is valid, it's added to your current MyBlock message. That message is serialized to binary (protobufs does this for you), hashed and then your node makes an RPC to Bitcoin telling it what the current extra hash is. When Bitcoin finds a Bitcoin-format block of the right difficulty for your network, it informs your software and passes the block header, coinbase transaction and merkle branch to it. Your node combines them together into a BitcoinData message, which is then glued together with your alternative chains block. This "superblock" is then broadcast via your independent P2P network.

When a node on your new network receives a superblock it does the following things:

# Verifies the MyBlock contents are correct, ie, that the transactions follow the rules.
# Verifies that the MyBlock prev hash makes it fit somewhere in the chain and that the difficulty is correct.
# Hashes the MyBlock structure and then verifies that this hash appears in the BitcoinData coinbase scriptSig, in the right place.
# Extracts the merkle root of the Bitcoin format block from the header and then verifies that the coinbase tx provided did, in fact, exist in that block (using the branch, root, tx and header together).
# Verifies that the hash of the Bitcoin format block header is below the difficulty found in the MyBlock structure.

You've now verified that a sufficiently hard proof of work was done over the contents of the MyBlock structure, so your node can relay the newly found block (or if you don't use a P2P network make it available on your server, etc).

On the other side when Bitcoin finds a block that is correct for the Bitcoin network and chain, it broadcasts it and obviously the hash of your MyBlock is included. Fortunately this is only an additional 33 bytes overhead so nobody cares about it - the pollution of the financial chain is both trivial and constant. Note that regular Bitcoin nodes just ignore this extra hash, it doesn't mean anything to them.

== Handling your new block chain ==

You have to handle re-organizations. This is a standard part of the block chain algorithm. When a re-org occurs you have to verify that the state of your world still makes sense. For example in the new chain maybe somebody else now owns a resource you thought you owned. It's up to you how to inform your users of these events and what app specific logic is appropriate here.

You can choose your own parameters for the new chain. As an example, Satoshi chose to target one new block every ten minutes as a tradeoff between latency and wasted work. You could choose something much larger (hours, days) or much faster if you're willing to tolerate more splits due to blocks being found simultaneously. Bitcoin retargets the difficulty roughly every two weeks. You could choose some other length of time.

To store the block chain, Satoshi chose to use Berkeley DB as a way to index from transactions to the blocks they appeared in (amongst other things). You could use any database you liked.

== Paying for resources on alternative chains with Bitcoins ==

A commonly cited reason for putting DNS related data into the financial chain is the desire to pay for names with Bitcoins. You can do this with an independent chain too, because you make the rules and can link the two chains together as you see fit.

To start, decide on the purpose of your payments and who will receive the coins - if anyone. In the case of a DNS system, there are two reasons you might want to pay for names:

# To prevent abuse by people claiming all interesting names via a dictionary attack.
# To incentivise people to run your software and mine on your alternative chain.

In the first case really nobody should receive the payment. The money is being put up as a collateral and has no other use, so as long as it's sitting around unspent that is good enough. In the second case the payment should go to the miner working on the DNS chain.

To implement this we extend our hypothetical DNS transaction message like this:

message NameTx {
required string name = 1;
repeated bytes ip_addresses = 2;
required bytes pubkey = 3;
enum ClaimType {
NEW_NAME,
TRANSFER
}
required ClaimType type = 4;

// Only used if type == TRANSFER. The new owner of the name and signature proving current ownership.
optional bytes dest_pubkey = 5;
optional bytes signature = 6;

// Only used if type == NEW_NAME.
optional bytes collateral_signature = 7;
optional string miner_address = 8;
optional uint64 miner_fee = 9;
}

The collateral_signature field contains an ECDSA signature generated from a public key that holds some Bitcoins. The miner address is blank when the name purchaser creates the transaction and is filled out after a miner receives it, but before they begin working on it.

To buy a name that costs 10 BTC with a miner fee of 2 BTC, a user presses the "buy name" button in their DNS software. It talks to their local Bitcoin node via RPC and does the following:

# Creates a new Bitcoin address (key).
# Sends 10 BTC to the new address (a send-to-self transaction).
# Extracts the key from Bitcoin, meaning it's no longer available to spend in your wallet.
# Stores the key in a local DNS data file ("wallet") somewhere.
# Sets the miner_fee field to the pre-agreed value of 2 BTC.
# Takes the public key part and uses it to sign a version of the NameTx that lacks collateral_signature (a signature can't sign itself) and miner_address.
# The signature is placed in collateral_signature field.
# The transaction is sent to a miner who charges 2 BTC.

When the miner receives the transaction, it verifies that the 10 BTC is not spent:

# The ECDSA public key recovery algorithm is run on the collateral_signature. It can yield several possible keys.
# The public keys recovered are used to verify the signature is correct. This step also figures out which of the possible keys is the right one.
# The correct public key is turned into a Bitcoin address (by hashing it)
# The DNS node software queries Bitcoin to discover whether that address has 10 BTC associated with it, or whether the balance of that address is lower. Note that todays software does not index the balance of every address in the system, but it can be added (the Block Explorer does this).
# If the address does indeed have 10 unspent Bitcoins then the collateral is present and it's OK to serve the name

The miner then creates a new Bitcoin address for themselves and sets miner_address to contain it, then includes it into the current block being worked on. After a block matching the DNS chains difficulty is found, it is broadcast. Other nodes do the following:

# For each transaction, repeat the verification steps to ensure the collateral is not spent.
# Check the balance of the miners own address.
# If the balance is not yet equal to miner_fee, the name is put into a "pending" state in which it is owned but not served in response to DNS queries.

The user observes the broadcast and sees that their name is now pending payment, so they send 2 BTC to the address they find in their transaction. As nodes notice the payment becoming confirmed they start responding to DNS queries for that name (ie, the ownership process is complete).

When the user gets tired of owning the name, he can simply re-import the collateral key into his wallet and spend the coins. The DNS network will soon observe that the coins are spent and make the name available for purchasing by somebody else.

== Incentivising non-resource based chains ==

It's possible to incentivise mining on an alt-chain even if that chain does not have any concept of ownership, ie, if the act of finding a block itself is what is being paid for. An example of this is a timestamping chain in which presence in a block alone is sufficient to satisfy the user.

To implement this, set up a new chain as normal. Blocks in this new chain arrange transactions into a merkle tree in the same manner as Bitcoin does. A client that wants something incorporated into a block connects directly to some miners and submits their transaction. The miners add their address to the transaction as normal. Once a miner finds a block, it immediately sends the block to connected clients whose transactions made it in, but does not broadcast the new block to other miners. The clients respond with a valid Bitcoin transaction which pays for block inclusion. Once all clients have paid up the transaction is broadcast.

If a client has disconnected or does not pay quickly enough, their transaction can be replaced inside the block with its hash. In this way the blocks validity is preserved because the merkle tree is still valid. The newly found alt-block is broadcast, minus the transaction of the delinquent customer. As long as clients are still connected the payment process for all found transactions can be completed quickly: it would only take a few seconds to gather the payments and broadcast those on the Bitcoin network, minimizing the chance of a race that would require you to trust the miner to reinclude your transactions in the next block despite having already been paid.

== Mining on the alt-chain but not Bitcoin ==

So far we've considered a scheme in which all alt-chain miners simultaneously mine on Bitcoin. It's possible some people may wish to mine on your chain but not Bitcoin, perhaps because the cost of keeping up with the Bitcoin transaction rate has become too high for them to bother.

To mine without an attached Bitcoin node, your software can simply implement the same getwork protocol Bitcoin itself does. When a mining tool requests work your program would generate a correctly formatted but ultimately bogus Bitcoin block. The contents of this block don't need to be correct because it will never be broadcast on the Bitcoin network, for example, the prevBlockHash field can be all zeros. It exists purely for backwards compatibility. Whilst the block needs a valid merkle root and a coinbase transaction, no other transactions are required and the only part of the coinbase tx that matters is the part holding the hash.

== Scaling up ==

In the simple scheme each alt-chain being worked on needs 33 bytes in the Bitcoin coinbase transaction (1 for the length and 32 for the hash). Note that if there are two independent miners working on two different alt-chains, you still only need 1 hash in the coinbase scriptSig because the hash isn't meaningful to anyone else on the Bitcoin network. If miners only want to work a handful of chains this overhead is trivially dwarfed by the rest of the data in a Bitcoin block.

But if a miner wishes to work on hundreds, thousands or millions of alternative chains the size of the coinbase scriptSig would balloon and become unworkable. To solve this, the hash stored in the scriptSig can be the root of yet another merkle tree, this time a tree over the hashes of all blocks being worked on. The BitcoinData message is extended like this:

message MyBlock {
required bytes prev_block_hash = 1;
required uint32 difficulty = 2;
required uint32 time = 3;

repeated MyTx transactions = 4;
}

message SuperBlock {
required MyBlock my_data = 1;
required BitcoinData bitcoin_data = 2;
}

message BitcoinData {
// A Bitcoin format block header. Because it's in Satoshis custom format we represent this as a byte array.
required bytes header = 1;

// The first transaction from the block.
required bytes coinbase_tx = 2;

// The merkle branch linking the coinbase transaction to the header.
required bytes coinbase_merkle_branch = 3;

// The merkle branch linking MyBlock to the merkle root in the coinbase_tx.
required bytes altblock_merkle_branch = 4;
}

The verification step becomes a bit more complex:

# Verify the header is of sufficient difficulty for the alt-chain
# Verify coinbase_tx was a part of that block by checking the coinbase_merkle_branch is linked to the merkle root in the header.
# Extract the root of the second merkle tree from the coinbase_tx (call it 2MR).
# Hash the alt-chain block (my_data), verify that altblock_merkle_branch links the my_data hash to 2MR.

You have now proven that the MyBlock instance was worked on, along with perhaps thousands of other chains you don't have to know anything about.

This is an advanced technique which is probably not worth implementing unless the additional scalability is required. It can be introduced in a backwards compatible manner for new chains without impacting older networks.

=== Protecting against double proof ===

The merkle tree approach to scalability comes with a caveat. If naïvely implemented, a miner could cheat the proof-of-work system by putting more than one alt-chain block header into one Bitcoin block. This "cheating" would not cause a problem if the alt-chain blocks all had the same previous-block hash: one or another would win the race, as happens when competing blocks enter the network. The problem would arise if a linked series of alt-chain blocks all existed in one Bitcoin block's auxiliary merkle trees. The miner could work on them all at once, getting more from his hashes than difficulty warrants.

Namecoin's [http://dot-bit.org/forum/viewtopic.php?f=5&t=269&start=11 solution] is to constrain the paths by which alt-chain blocks may be embedded in Bitcoin blocks. This works, but it complicates the picture for miners and chain designers in a future with many alternative chains.

A better solution for new chains is to forbid multiple blocks from having the same proof of work hash - the hash measured against the difficulty target would need to be unique over all blocks. This means you can't embed a series of blocks into the same merkle tree and win them all simultaneously as the network would accept only one.
'''However''', this "better solution" does not protect against multiple blocks competing for the same proof-of-work, and could subject your blockchain to nothing-at-stake attacks.
So don't use it unless you first make sure this isn't possible.

== Generalized proof of work ==

Hashes embedded in transactions and headers, merkle branches, and [[Nonce|nonces]] all contribute to the goal of [[Proof of work|proving work]] on a block header. One can express all as sequences of these basic operations:

* prepend a byte string to the current data
* append a byte string to the current data
* hash the current data

For maximum flexibility, a work-sharing chain's block acceptance algorithm might accept proof in the form of a script using just these operations. The script would receive as input an alternative chain block header, and the hash of its output would have to satisfy the chain's difficulty.

This design would even support plain Bitcoin proof of work, where the "header" consists of all [[Protocol Specification#block|Bitcoin block header fields]] except the nonce, and the proof-of-work script simply appends the nonce. Thus, one can think of the work-sharing rules as an extension of the original Bitcoin rules.

Note that any naive implementation of this idea would let people create proofs-of-work by including data in a Bitcoin transaction, which would be accepted into a block.

==Modern non-Bitcoin blockchain designs==

Below are a few brief examples of designs for blockchains used by alternative chains. For further information, you should consult the documentation of those specific chains.

===Account-based smart-contract platforms===

Bitcoin represents spendable value as unspent transaction outputs. Account-based platforms instead maintain accounts as part of a shared state. Ethereum, for example, distinguishes externally owned accounts controlled by keys from contract accounts controlled by deployed code; both can hold assets and interact with smart contracts. This permits a general-purpose execution environment rather than the application-specific transaction structures proposed in the historical design below.

===Proof-of-stake chains===

An alternative chain does not have to use proof of work or share Bitcoin miners. Proof-of-stake systems use validators that place assets at risk and can lose stake for provably dishonest behaviour. Ethereum replaced its proof-of-work consensus with proof of stake in 2022; its validators stake ETH, check proposed blocks, attest to blocks and are periodically selected to propose new ones.

===Application-specific and modular chains===

Some frameworks provide SDKs which are designed for projects to build sovereign, application-specific blockchains. For instance, Cosmos separates consensus, networking and block production from application logic and state-machine modules. This allows a chain to define its own transactions, state and governance without using Bitcoin's proof-of-work or transaction format.

===Permissioned blockchains===

Public Bitcoin-like networks allow participation without approval. Permissioned blockchains instead identify participants and control their roles. Such networks may use a blockchain data structure while relying on organizational identity and governance rather than anonymous miners or validators. An example of this type of network is Hyperledger Fabric.

==References==
<references />

==External Links==

* [https://bitcointalk.org/index.php?topic=6197.0 BitDNS in the words of Satoshi]
* [http://dot-bit.org/Merged_Mining Merged Mining] in Namecoin
* [http://dot-bit.org/forum/viewtopic.php?f=5&t=269 Namecoin forum discussion]
* [https://bitcointalk.org/index.php?topic=46927.msg572981#msg572981 Forum thread about double proof]
* [http://www.cryptocoincharts.info/ Long-term price charts]
* [https://www.slideshare.net/ripper234/alternative-payment-technologies-march-2013/ Presentation about major altcoins]

----

See also [[Intrinsic worth brainstorming]].

[[Category:Technical]]
[[Category:Alternative cryptocurrencies]]

Alternative chain

2026-07-20T08:40:27Z

NotATether: Add modern blockchains

An '''alternative chain''' is a system using the block chain algorithm to achieve distributed consensus on a particular topic. Alternative chains may share miners with a '''parent''' network such as Bitcoin's; this is called '''merged mining'''. The digital currencies of alternative chains are commonly called alternative currencies, or '''altcoins''' for short.

Alternative chains have been suggested as ways to implement [http://www.dot-bit.org DNS], [[Bitcoin OTC|P2P currency exchanges]], SSL certificate authorities, timestamping, file storage and voting systems.

== Context ==

The term ''alternative chain'' is used narrowly in the original sections below for an independent Bitcoin-style proof-of-work chain, particularly one that can share work with Bitcoin miners. The design grew out of early discussions such as the BitcoinTalk thread "BitDNS and Generalizing Bitcoin", where participants considered separate blockchains for decentralized DNS and other applications.<ref name="bitdns">{{cite btct|id=1790|title=BitDNS and Generalizing Bitcoin|date=15 November 2010}}</ref>

[[Namecoin]] became the best-known early implementation of this idea. Its project describes Namecoin as a Bitcoin-based key/value registration and transfer system for DNS, identities and other internet-infrastructure uses, and says it was the first fork of Bitcoin and the first system to implement merged mining and decentralized DNS.<ref name="namecoin">{{cite web|url=https://www.namecoin.org/|title=Namecoin|publisher=Namecoin|accessdate=20 July 2026}}</ref>

Modern usage is broader. An independent blockchain need not copy Bitcoin's transaction model, proof-of-work consensus, block format or mining system. The following families overlap; they describe different execution, consensus and governance choices rather than mutually exclusive categories.

== Objective ==

Bitcoin uses the [[block chain]] algorithm to achieve distributed consensus on who owns what coins. Block chains were invented specifically for the Bitcoin project but they can be applied anywhere a distributed consensus needs to be established in the presence of malicious or untrustworthy actors.

Whilst it's possible to abuse the Bitcoin financial block chain for other purposes, it's better to set up an alternative network and chain which share the same miners. There are several reasons to do this.

* The block chain is a large, complex data structure shared between many people. Verifying its integrity requires many slow (and thus expensive) operations like ECDSA verifications and disk seeks. Everyone who takes part in Bitcoin today runs a node and thus maintains the whole thing. Whilst in future end-users will probably use more efficient but slightly less secure modes (SPV), merchants and miners will probably always pay the full costs for the upkeep of this shared data structure. All these people today are united by a common interest in a new form of payments. They may or may not also be interested in other schemes. So one reason to keep the Bitcoin chain for finance is it's unfair to externalize the costs of unrelated schemes onto people who are interested only in payments - the canonical example being merchants. Increasing the cost of accepting Bitcoins for goods and services hurts everyone who uses the system by reducing the number of merchants or increasing their costs.

* Another reason is that it's just bad engineering to cram every possible distributed quorum into the design constraints of Bitcoin. The transaction format Bitcoin uses is flexible but ultimately designed for finance. You cannot leave out the "value" field. It's always there, even if it'd make no sense for your particular application. Building non-financial applications on top of a financial system results in bizarre protocols and code that are difficult to understand, leading to maintainability problems.

* One final reason is that [[Satoshi Nakamoto|Satoshi]] was opposed to putting non-Bitcoin related data into the main chain. As creator of the system, his opinion should carry a lot of weight with anyone serious about extending it.

=== Designing a new network ===

To create a new network that uses Nakamoto block chains, you need to start by defining what a transaction in your new network means. Bitcoin transactions split and combine value using scripts, but yours don't have to do that. They could be anything. Here's an example of a simple DNS style "transaction" described using [http://code.google.com/p/protobuf/ Google protocol buffers] syntax.

message NameTx {
required string name = 1;
repeated bytes ip_addresses = 2;
required bytes pubkey = 3;
enum ClaimType {
NEW_NAME,
TRANSFER
}
required ClaimType type = 4;

// Only used if type == TRANSFER. The new owner of the name and signature proving current ownership.
optional bytes dest_pubkey = 5;
optional bytes signature = 6;
}

This is very different to a Bitcoin style transaction. There's no concept of inputs, outputs, addresses, values or scripts. It's got what you need for a very simple DNS style scheme (that lacks abuse controls etc) and nothing more. There's also no concept of a "coinbase" transaction.

The block definition is also up to you. It does not have to be formatted in the same way as Satoshi chose, but you need most of the same conceptual parts. You also need to store something else, some data from Bitcoin. Here's a minimal example of what's needed:

message MyBlock {
required bytes prev_block_hash = 1;
required uint32 difficulty = 2;
required uint32 time = 3;

repeated MyTx transactions = 4;
}

message SuperBlock {
required MyBlock my_data = 1;
required BitcoinData bitcoin_data = 2;
}

It's important to observe what we don't have as well as what we do. We don't have the following fields from Satoshis format:

# version: protobufs handles the versioning of binary data formats for us
# merkle root: you can choose to arrange your transactions into a merkle root if you like, so you can use the same disk space reclamation trick Satoshi did. But it's strictly optional. If you want to simplify things down you can skip it.
# nonce

== Sharing work ==

The bitcoin_data field is how you share work with miners today (assuming they opt in by installing your software alongside their bitcoin node). It's defined like this:

message BitcoinData {
// A Bitcoin format block header. Because it's in Satoshis custom format we represent this as a byte array.
required bytes header = 1;

// The first transaction from the block.
required bytes coinbase_tx = 2;

// The merkle branch linking the coinbase transaction to the header.
required bytes coinbase_merkle_branch = 3;

// The coinbase scriptSig contains bits of data in order. Which one is our hash?
required int coinbase_tx_index = 4;
}

All you need to share work is the above four things.

A [[wikipedia:Merkle tree|merkle tree]] is a data structure in which each node in the tree is a hash. The leaf nodes are hashes of the things you want to include in the tree. The interior nodes are hashes of the concatenations of the child nodes. A merkle branch is a part of a merkle tree which allows you to cryptographically prove that something you're given was in the tree, without needing everything that was in the tree. They are calculated by the CBlock::GetMerkleBranch() function in the Bitcoin code.

We store a merkle branch here for efficiency. It means no matter how large the current Bitcoin block is, your alternative network only needs to handle a small amount of data. You could just store the entire Bitcoin block - that would be simpler but inefficient.

The merkle branch links the coinbase transaction to the block header, so you can prove it was in that block. The coinbase TX is a regular Bitcoin coinbase (that makes new coins and claims fees), except the scriptSig on its input contains an extra entry that todays scriptSigs don't. That extra entry is a hash of your block structure. The coinbase scriptSig today is formatted like this:

void IncrementExtraNonce(CBlock* pblock, CBlockIndex* pindexPrev, unsigned int& nExtraNonce, int64& nPrevTime)
{
.....
pblock->vtx[0].vin[0].scriptSig = CScript() << pblock->nBits << CBigNum(nExtraNonce);
.....
}

Just the difficulty bits and the "extra nonce". But it's actually allowed to contain anything, as long as it's not too big. So in your new blocks it'd be:

<MyBlock hash> <nBits> <nExtraNonce>

To get the MyBlock hash into Bitcoin requires a presently unimplemented RPC command, "setextrahashes". It'd update a global list and the IncrementExtraNonce function would include the extra hashes when the scriptSig is built. This is a very simple change to Bitcoin.

In the scriptSig above the coinbase_tx_index would be zero. It's possible to work on an arbitrary number of alternative chains simultaneously:

<MyBlock hash> <SomeOtherChainBlock hash> <nBits> <nExtraNonce>

in which case the BitcoinData message for SomeOtherChain would be 1 rather than zero.

A more complex change is the other new RPC. Because you have your own chain, it has its own difficulty. Most likely it'll be different to Bitcoins own. So you need a way to tell Bitcoin "when you find a block that matches an extradifficulty, please let me know". To mine on multiple difficulties at once, the node vends work (via getwork) matching the easiest difficulty. When a miner reports finding a solution the difficulty is checked to see which chains it is sufficiently difficult for.

Important note: Your chain has its own difficulty and as such the block creation rate is independent of how much mining takes place.

== Independent node software ==

Your new network has its own codebase. It can be written in whatever language you like, use whatever P2P protocol you like, store its data however you like and so on.

When a node on your network receives a message informing it about a new transaction, it verifies that transaction follows the rules of your network. To use our simple DNS example it would verify that if you're claiming a new name, it doesn't already exist and if you're transferring a name that the signatures are correct.

If the transaction is valid, it's added to your current MyBlock message. That message is serialized to binary (protobufs does this for you), hashed and then your node makes an RPC to Bitcoin telling it what the current extra hash is. When Bitcoin finds a Bitcoin-format block of the right difficulty for your network, it informs your software and passes the block header, coinbase transaction and merkle branch to it. Your node combines them together into a BitcoinData message, which is then glued together with your alternative chains block. This "superblock" is then broadcast via your independent P2P network.

When a node on your new network receives a superblock it does the following things:

# Verifies the MyBlock contents are correct, ie, that the transactions follow the rules.
# Verifies that the MyBlock prev hash makes it fit somewhere in the chain and that the difficulty is correct.
# Hashes the MyBlock structure and then verifies that this hash appears in the BitcoinData coinbase scriptSig, in the right place.
# Extracts the merkle root of the Bitcoin format block from the header and then verifies that the coinbase tx provided did, in fact, exist in that block (using the branch, root, tx and header together).
# Verifies that the hash of the Bitcoin format block header is below the difficulty found in the MyBlock structure.

You've now verified that a sufficiently hard proof of work was done over the contents of the MyBlock structure, so your node can relay the newly found block (or if you don't use a P2P network make it available on your server, etc).

On the other side when Bitcoin finds a block that is correct for the Bitcoin network and chain, it broadcasts it and obviously the hash of your MyBlock is included. Fortunately this is only an additional 33 bytes overhead so nobody cares about it - the pollution of the financial chain is both trivial and constant. Note that regular Bitcoin nodes just ignore this extra hash, it doesn't mean anything to them.

== Handling your new block chain ==

You have to handle re-organizations. This is a standard part of the block chain algorithm. When a re-org occurs you have to verify that the state of your world still makes sense. For example in the new chain maybe somebody else now owns a resource you thought you owned. It's up to you how to inform your users of these events and what app specific logic is appropriate here.

You can choose your own parameters for the new chain. As an example, Satoshi chose to target one new block every ten minutes as a tradeoff between latency and wasted work. You could choose something much larger (hours, days) or much faster if you're willing to tolerate more splits due to blocks being found simultaneously. Bitcoin retargets the difficulty roughly every two weeks. You could choose some other length of time.

To store the block chain, Satoshi chose to use Berkeley DB as a way to index from transactions to the blocks they appeared in (amongst other things). You could use any database you liked.

== Paying for resources on alternative chains with Bitcoins ==

A commonly cited reason for putting DNS related data into the financial chain is the desire to pay for names with Bitcoins. You can do this with an independent chain too, because you make the rules and can link the two chains together as you see fit.

To start, decide on the purpose of your payments and who will receive the coins - if anyone. In the case of a DNS system, there are two reasons you might want to pay for names:

# To prevent abuse by people claiming all interesting names via a dictionary attack.
# To incentivise people to run your software and mine on your alternative chain.

In the first case really nobody should receive the payment. The money is being put up as a collateral and has no other use, so as long as it's sitting around unspent that is good enough. In the second case the payment should go to the miner working on the DNS chain.

To implement this we extend our hypothetical DNS transaction message like this:

message NameTx {
required string name = 1;
repeated bytes ip_addresses = 2;
required bytes pubkey = 3;
enum ClaimType {
NEW_NAME,
TRANSFER
}
required ClaimType type = 4;

// Only used if type == TRANSFER. The new owner of the name and signature proving current ownership.
optional bytes dest_pubkey = 5;
optional bytes signature = 6;

// Only used if type == NEW_NAME.
optional bytes collateral_signature = 7;
optional string miner_address = 8;
optional uint64 miner_fee = 9;
}

The collateral_signature field contains an ECDSA signature generated from a public key that holds some Bitcoins. The miner address is blank when the name purchaser creates the transaction and is filled out after a miner receives it, but before they begin working on it.

To buy a name that costs 10 BTC with a miner fee of 2 BTC, a user presses the "buy name" button in their DNS software. It talks to their local Bitcoin node via RPC and does the following:

# Creates a new Bitcoin address (key).
# Sends 10 BTC to the new address (a send-to-self transaction).
# Extracts the key from Bitcoin, meaning it's no longer available to spend in your wallet.
# Stores the key in a local DNS data file ("wallet") somewhere.
# Sets the miner_fee field to the pre-agreed value of 2 BTC.
# Takes the public key part and uses it to sign a version of the NameTx that lacks collateral_signature (a signature can't sign itself) and miner_address.
# The signature is placed in collateral_signature field.
# The transaction is sent to a miner who charges 2 BTC.

When the miner receives the transaction, it verifies that the 10 BTC is not spent:

# The ECDSA public key recovery algorithm is run on the collateral_signature. It can yield several possible keys.
# The public keys recovered are used to verify the signature is correct. This step also figures out which of the possible keys is the right one.
# The correct public key is turned into a Bitcoin address (by hashing it)
# The DNS node software queries Bitcoin to discover whether that address has 10 BTC associated with it, or whether the balance of that address is lower. Note that todays software does not index the balance of every address in the system, but it can be added (the Block Explorer does this).
# If the address does indeed have 10 unspent Bitcoins then the collateral is present and it's OK to serve the name

The miner then creates a new Bitcoin address for themselves and sets miner_address to contain it, then includes it into the current block being worked on. After a block matching the DNS chains difficulty is found, it is broadcast. Other nodes do the following:

# For each transaction, repeat the verification steps to ensure the collateral is not spent.
# Check the balance of the miners own address.
# If the balance is not yet equal to miner_fee, the name is put into a "pending" state in which it is owned but not served in response to DNS queries.

The user observes the broadcast and sees that their name is now pending payment, so they send 2 BTC to the address they find in their transaction. As nodes notice the payment becoming confirmed they start responding to DNS queries for that name (ie, the ownership process is complete).

When the user gets tired of owning the name, he can simply re-import the collateral key into his wallet and spend the coins. The DNS network will soon observe that the coins are spent and make the name available for purchasing by somebody else.

== Incentivising non-resource based chains ==

It's possible to incentivise mining on an alt-chain even if that chain does not have any concept of ownership, ie, if the act of finding a block itself is what is being paid for. An example of this is a timestamping chain in which presence in a block alone is sufficient to satisfy the user.

To implement this, set up a new chain as normal. Blocks in this new chain arrange transactions into a merkle tree in the same manner as Bitcoin does. A client that wants something incorporated into a block connects directly to some miners and submits their transaction. The miners add their address to the transaction as normal. Once a miner finds a block, it immediately sends the block to connected clients whose transactions made it in, but does not broadcast the new block to other miners. The clients respond with a valid Bitcoin transaction which pays for block inclusion. Once all clients have paid up the transaction is broadcast.

If a client has disconnected or does not pay quickly enough, their transaction can be replaced inside the block with its hash. In this way the blocks validity is preserved because the merkle tree is still valid. The newly found alt-block is broadcast, minus the transaction of the delinquent customer. As long as clients are still connected the payment process for all found transactions can be completed quickly: it would only take a few seconds to gather the payments and broadcast those on the Bitcoin network, minimizing the chance of a race that would require you to trust the miner to reinclude your transactions in the next block despite having already been paid.

== Mining on the alt-chain but not Bitcoin ==

So far we've considered a scheme in which all alt-chain miners simultaneously mine on Bitcoin. It's possible some people may wish to mine on your chain but not Bitcoin, perhaps because the cost of keeping up with the Bitcoin transaction rate has become too high for them to bother.

To mine without an attached Bitcoin node, your software can simply implement the same getwork protocol Bitcoin itself does. When a mining tool requests work your program would generate a correctly formatted but ultimately bogus Bitcoin block. The contents of this block don't need to be correct because it will never be broadcast on the Bitcoin network, for example, the prevBlockHash field can be all zeros. It exists purely for backwards compatibility. Whilst the block needs a valid merkle root and a coinbase transaction, no other transactions are required and the only part of the coinbase tx that matters is the part holding the hash.

== Scaling up ==

In the simple scheme each alt-chain being worked on needs 33 bytes in the Bitcoin coinbase transaction (1 for the length and 32 for the hash). Note that if there are two independent miners working on two different alt-chains, you still only need 1 hash in the coinbase scriptSig because the hash isn't meaningful to anyone else on the Bitcoin network. If miners only want to work a handful of chains this overhead is trivially dwarfed by the rest of the data in a Bitcoin block.

But if a miner wishes to work on hundreds, thousands or millions of alternative chains the size of the coinbase scriptSig would balloon and become unworkable. To solve this, the hash stored in the scriptSig can be the root of yet another merkle tree, this time a tree over the hashes of all blocks being worked on. The BitcoinData message is extended like this:

message MyBlock {
required bytes prev_block_hash = 1;
required uint32 difficulty = 2;
required uint32 time = 3;

repeated MyTx transactions = 4;
}

message SuperBlock {
required MyBlock my_data = 1;
required BitcoinData bitcoin_data = 2;
}

message BitcoinData {
// A Bitcoin format block header. Because it's in Satoshis custom format we represent this as a byte array.
required bytes header = 1;

// The first transaction from the block.
required bytes coinbase_tx = 2;

// The merkle branch linking the coinbase transaction to the header.
required bytes coinbase_merkle_branch = 3;

// The merkle branch linking MyBlock to the merkle root in the coinbase_tx.
required bytes altblock_merkle_branch = 4;
}

The verification step becomes a bit more complex:

# Verify the header is of sufficient difficulty for the alt-chain
# Verify coinbase_tx was a part of that block by checking the coinbase_merkle_branch is linked to the merkle root in the header.
# Extract the root of the second merkle tree from the coinbase_tx (call it 2MR).
# Hash the alt-chain block (my_data), verify that altblock_merkle_branch links the my_data hash to 2MR.

You have now proven that the MyBlock instance was worked on, along with perhaps thousands of other chains you don't have to know anything about.

This is an advanced technique which is probably not worth implementing unless the additional scalability is required. It can be introduced in a backwards compatible manner for new chains without impacting older networks.

=== Protecting against double proof ===

The merkle tree approach to scalability comes with a caveat. If naïvely implemented, a miner could cheat the proof-of-work system by putting more than one alt-chain block header into one Bitcoin block. This "cheating" would not cause a problem if the alt-chain blocks all had the same previous-block hash: one or another would win the race, as happens when competing blocks enter the network. The problem would arise if a linked series of alt-chain blocks all existed in one Bitcoin block's auxiliary merkle trees. The miner could work on them all at once, getting more from his hashes than difficulty warrants.

Namecoin's [http://dot-bit.org/forum/viewtopic.php?f=5&t=269&start=11 solution] is to constrain the paths by which alt-chain blocks may be embedded in Bitcoin blocks. This works, but it complicates the picture for miners and chain designers in a future with many alternative chains.

A better solution for new chains is to forbid multiple blocks from having the same proof of work hash - the hash measured against the difficulty target would need to be unique over all blocks. This means you can't embed a series of blocks into the same merkle tree and win them all simultaneously as the network would accept only one.
'''However''', this "better solution" does not protect against multiple blocks competing for the same proof-of-work, and could subject your blockchain to nothing-at-stake attacks.
So don't use it unless you first make sure this isn't possible.

== Generalized proof of work ==

Hashes embedded in transactions and headers, merkle branches, and [[Nonce|nonces]] all contribute to the goal of [[Proof of work|proving work]] on a block header. One can express all as sequences of these basic operations:

* prepend a byte string to the current data
* append a byte string to the current data
* hash the current data

For maximum flexibility, a work-sharing chain's block acceptance algorithm might accept proof in the form of a script using just these operations. The script would receive as input an alternative chain block header, and the hash of its output would have to satisfy the chain's difficulty.

This design would even support plain Bitcoin proof of work, where the "header" consists of all [[Protocol Specification#block|Bitcoin block header fields]] except the nonce, and the proof-of-work script simply appends the nonce. Thus, one can think of the work-sharing rules as an extension of the original Bitcoin rules.

Note that any naive implementation of this idea would let people create proofs-of-work by including data in a Bitcoin transaction, which would be accepted into a block.

==Modern non-Bitcoin blockchain designs==

Below are a few brief examples of designs for blockchains used by alternative chains. For further information, you should consult the documentation of those specific chains.

===Account-based smart-contract platforms===

Bitcoin represents spendable value as unspent transaction outputs. Account-based platforms instead maintain accounts as part of a shared state. Ethereum, for example, distinguishes externally owned accounts controlled by keys from contract accounts controlled by deployed code; both can hold assets and interact with smart contracts. This permits a general-purpose execution environment rather than the application-specific transaction structures proposed in the historical design below.

===Proof-of-stake chains===

An alternative chain does not have to use proof of work or share Bitcoin miners. Proof-of-stake systems use validators that place assets at risk and can lose stake for provably dishonest behaviour. Ethereum replaced its proof-of-work consensus with proof of stake in 2022; its validators stake ETH, check proposed blocks, attest to blocks and are periodically selected to propose new ones.

===Application-specific and modular chains===

Some frameworks provide SDKs which are designed for projects to build sovereign, application-specific blockchains. For instance, Cosmos separates consensus, networking and block production from application logic and state-machine modules. This allows a chain to define its own transactions, state and governance without using Bitcoin's proof-of-work or transaction format.

===Permissioned blockchains===

Public Bitcoin-like networks allow participation without approval. Permissioned blockchains instead identify participants and control their roles. Such networks may use a blockchain data structure while relying on organizational identity and governance rather than anonymous miners or validators. An example of this type of network is Hyperledger Fabric.

==References==
<references />

==External Links==

* [https://bitcointalk.org/index.php?topic=6197.0 BitDNS in the words of Satoshi]
* [http://dot-bit.org/Merged_Mining Merged Mining] in Namecoin
* [http://dot-bit.org/forum/viewtopic.php?f=5&t=269 Namecoin forum discussion]
* [https://bitcointalk.org/index.php?topic=46927.msg572981#msg572981 Forum thread about double proof]
* [http://www.cryptocoincharts.info/ Long-term price charts]
* [https://www.slideshare.net/ripper234/alternative-payment-technologies-march-2013/ Presentation about major altcoins]

----

See also [[Intrinsic worth brainstorming]].

[[Category:Technical]]
[[Category:Alternative cryptocurrencies]]

Alphapoint

2026-07-19T16:53:18Z

NotATether: Clean up page

{{infobox company
|name=AlphaPoint
|industry=Digital-asset infrastructure
|foundation=2013
|keypeople=Igor Telyatnikov (co-founder and CEO) Joe Ventura (founder and CIO)
|website=https://alphapoint.com/
}}

'''AlphaPoint''' is a financial-technology company that develops digital-asset infrastructure for institutions. Its current platform covers treasury operations, trading venues, payments and liquidity services for banks, governments, fintech companies, exchanges and brokerages.<ref name="homepage">{{cite web|url=https://alphapoint.com/|title=Alphapoint - Financial infrastructure for the digital asset era|publisher=AlphaPoint|accessdate=19 July 2026}}</ref>

==History==
AlphaPoint was founded in 2013 by people with experience building institutional trading systems. The company's timeline says that its first production exchange deployment was for Bitt.com in 2014. It later worked on projects including Royal Mint Gold with CME Group and infrastructure for El Salvador's Chivo wallet.<ref name="about">{{cite web|url=https://alphapoint.com/about|title=About Alphapoint|publisher=AlphaPoint|accessdate=19 July 2026}}</ref>

==Services==
AlphaPoint describes its products as infrastructure for managing digital assets across wallets, blockchains and counterparties; operating trading venues; and connecting exchanges, brokerages and other trading platforms to liquidity.<ref name="homepage" /> The company says that its infrastructure has processed more than US$1 trillion and has supported more than 150 institutions worldwide.<ref name="homepage" /><ref name="about" />

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

==References==
<references />

[[Category:Software]]

Allbitcoincasino

2026-07-19T16:44:37Z

NotATether: Reflect that the site is out-of-date

'''AllBitcoinCasino.com''' is a website that publishes reviews and rankings of online casinos accepting [[Bitcoin]].

==Status==
The site remains online, but appears to be a single-page stub. As of July 2026, the homepage listed only 3 casinos and has not been updated since 2017. The site's rankings and other promotional information are therefore out of date.<ref>{{cite web|url=http://allbitcoincasino.com/|title=Best Bitcoin Casinos 2017 - Updated Gambling Reviews|publisher=All Bitcoin Casino|accessdate=19 July 2026}}</ref>

==External links==
* [http://allbitcoincasino.com/ Official website]

==References==
<references />

[[Category:Gambling]]

Alfacash

2026-07-19T16:34:22Z

NotATether: Clean up page

{{infobox company
|name=Alfacash
|industry=[[Exchange]]
|foundation=May 2012
|website=https://www.alfa.cash/
}}
'''Alfacash''' is a fixed-rate, non-custodial cryptocurrency exchange service operating at <code>alfa.cash</code>. Its website advertises automatic coin swaps, an application programming interface (API), and referral and discount programs.<ref name="homepage">{{cite web|url=https://www.alfa.cash/|title=Alfacash - Buy, Sell & Exchange Bitcoin, Litecoin, Ethereum, XRP, EOS, Tether and many other digital assets and blockchain tokens|publisher=Alfacash|accessdate=19 July 2026}}</ref>

==History==
According to the company's history page, Alfacash was founded in May 2012 as an electronic-currency exchange service. It began accepting [[Bitcoin]] in early 2013 and added Litecoin and Dash later that year. The company introduced an automatic-exchange feature in 2015 and an API in 2017.<ref name="about">{{cite web|url=https://www.alfa.cash/about|title=About us|publisher=Alfacash|accessdate=19 July 2026}}</ref>

==Service==
The homepage describes the service as non-custodial and advertises fixed exchange rates and automatic swaps.<ref name="homepage" /> Its developer documentation provides endpoints for creating orders, obtaining rates and order status, validating addresses, checking exchange limits, and retrieving the supported-currency list.<ref>{{cite web|url=https://www.alfa.cash/developers|title=Developers page|publisher=Alfacash|accessdate=19 July 2026}}</ref>

The available assets, payment methods and exchange directions can change; current availability is listed on the service rather than reproduced here.

==Restrictions and compliance==
Alfacash's terms prohibit use by nationals or residents of the United States and its territories, as well as people in other restricted jurisdictions. The terms state that transactions are checked on-chain under a Know Your Transaction process and may be delayed, suspended, cancelled or refunded according to risk scoring. Alfacash may request information about the source or destination of funds.<ref>{{cite web|url=https://www.alfa.cash/legal/terms-of-use|title=Terms of Use|publisher=Alfacash|date=26 March 2024|accessdate=19 July 2026}}</ref>

The company also publishes an anti-money-laundering policy describing customer identification, transaction monitoring and reporting procedures.<ref>{{cite web|url=https://www.alfa.cash/legal/anti-money-laundering-policy|title=Anti-Money Laundering Policy|publisher=Alfacash|date=19 October 2021|accessdate=19 July 2026}}</ref>

==External links==
* [https://www.alfa.cash/ Official website]
* [https://www.alfa.cash/about Company history]
* [https://www.alfa.cash/developers API documentation]
* [https://www.alfa.cash/legal Legal documents]

==References==
<references />

[[Category:Exchanges]]

Airdrop

2026-07-19T16:27:59Z

NotATether: Major rewrite - this page was essentially a skeleton.

{{seealso|List of alternative cryptocurrencies}}
'''Airdrop''' is a means of distributing cryptocurrency units to multiple wallet or distributed-ledger addresses. Projects often use airdrops to promote or bootstrap a new token by distributing it for free or in exchange for simple promotional tasks.<ref name="investopedia-airdrop">{{cite web|url=https://www.investopedia.com/terms/a/airdrop-cryptocurrency.asp|title=Guide to Cryptocurrency Airdrops: How They Work and What to Expect|author=The Investopedia Team|publisher=Investopedia|date=10 August 2025|accessdate=19 July 2026}}</ref><ref name="irs-airdrop">{{cite web|url=https://www.irs.gov/irb/2019-44_IRB|title=Revenue Ruling 2019-24|publisher=Internal Revenue Service|date=28 October 2019|accessdate=19 July 2026}}</ref>

==Types==
Common distribution methods include:

* '''Standard airdrops''', for which a participant supplies an eligible wallet address.
* '''Bounty airdrops''', which require tasks such as promoting a project or joining one of its communication channels.
* '''Holder airdrops''', allocated according to ownership of an existing token, sometimes in proportion to the amount held. Projects can determine eligibility from a snapshot of public blockchain balances.<ref name="investopedia-airdrop" />
* '''Fork-related airdrops''', in which units of a new cryptocurrency are distributed after a [[Hardfork|hard fork]] to addresses holding the legacy cryptocurrency. A hard fork does not necessarily include an airdrop, and the allocation need not be one-to-one.<ref name="irs-airdrop" />

==Security==
Airdrop offers may be used for phishing or other scams. Claimants should not disclose wallet private keys or recovery phrases and should be cautious about connecting a wallet to an unfamiliar website.<ref name="investopedia-airdrop" />

==References==
<references />

Adam Back

2026-07-17T09:13:32Z

NotATether: no need to mention the photographer

{{infobox person|name=Adam Back
|image=[[File:Adam Back 2025.png|256px]]
|caption=Adam Back in 2025.
|knownfor=[[Hashcash]]; co-founding [[Blockstream]]
|notableworks=[[Hashcash]]; ''Enabling Blockchain Innovations with Pegged Sidechains''
}}
'''Adam Back''' is a British computer scientist, cryptographer and cypherpunk who invented [[Hashcash]], a [[proof-of-work]] system announced in 1997 and later cited in the Bitcoin white paper, and co-founded the Bitcoin infrastructure company [[Blockstream]].<ref name="guardian">{{cite web|url=https://www.theguardian.com/technology/2026/apr/08/british-computer-scientist-adam-back-denies-he-is-bitcoin-developer-satoshi-nakamoto|title=British computer scientist denies he is bitcoin developer Satoshi Nakamoto|work=The Guardian|author=Down, Aisha|date=8 April 2026|accessdate=4 July 2026}}</ref><ref name="hashcash-papers">{{cite web|url=http://www.hashcash.org/papers/|title=Hashcash papers|publisher=Hashcash.org|accessdate=17 July 2026}}</ref><ref name="whitepaper">{{cite web|url=https://bitcoin.org/bitcoin.pdf|title=Bitcoin: A Peer-to-Peer Electronic Cash System|author=Nakamoto, Satoshi|date=31 October 2008|accessdate=4 July 2026}}</ref><ref name="blockstream-ceo">{{cite web|url=https://blockstream.com/press-releases/2016-10-03-blockstream-appoints-hashcash-inventor-dr-adam-back-as-ceo/|title=Blockstream Appoints Hashcash Inventor Dr. Adam Back as CEO|publisher=Blockstream|date=3 October 2016|accessdate=4 July 2026}}</ref>

==Background and Hashcash==
Back received a Ph.D. in distributed systems and computer science from the University of Exeter. Before Blockstream, he worked in cryptography, electronic cash and privacy technology and held senior roles at Zero-Knowledge Systems, Microsoft, EMC and VMware; he also co-founded the cloud-infrastructure company Pi Corporation.<ref name="blockstream-ceo" />

Back first announced Hashcash on the cypherpunks mailing list in March 1997. It was designed to deter email spam and denial-of-service attacks by requiring a sender to calculate a proof-of-work stamp that was moderately costly to produce but inexpensive for a recipient to verify. Back described the system formally in his 2002 paper ''Hashcash - A Denial of Service Counter-Measure''.<ref name="hashcash-papers" /><ref name="hashcash-paper">{{cite web|url=http://www.hashcash.org/papers/hashcash.pdf|title=Hashcash - A Denial of Service Counter-Measure|author=Back, Adam|date=1 August 2002|accessdate=17 July 2026}}</ref>

Bitcoin adapted this computational asymmetry for a different purpose. The white paper describes a proof-of-work system similar to Hashcash for Bitcoin's distributed timestamp server: miners repeatedly hash block headers until one satisfies the network target, and the accumulated work helps establish transaction order, resist double-spending and secure the issuance of new coins.<ref name="whitepaper" />

==Correspondence with Satoshi Nakamoto==
On 20 August 2008, [[Satoshi Nakamoto]] emailed Back a pre-release draft then titled ''Electronic Cash Without a Trusted Third Party'' and asked him to verify the citation to the Hashcash paper. Back confirmed the citation on 21 August and pointed Satoshi to Wei Dai's [[b-money]] proposal. Satoshi replied that he had not previously seen the b-money page and then contacted Dai to establish its publication date. The b-money citation became the first reference in the published Bitcoin white paper, while Hashcash appeared as the sixth.<ref name="back-statement">{{cite web|url=https://bitcoindefense.org/assets/documents/First-Witness-Statement-of-Dr-Adam-Back.pdf|title=First Witness Statement of Dr Adam Back|author=Back, Adam|date=17 July 2023|publisher=High Court of Justice|accessdate=17 July 2026}}</ref><ref name="copa-judgment">{{cite web|url=https://www.judiciary.uk/wp-content/uploads/2024/05/COPA-v-Wright-Judgment.pdf|title=Crypto Open Patent Alliance v Craig Steven Wright: Approved Judgment|author=Mellor, James|publisher=High Court of Justice of England and Wales|date=20 May 2024|accessdate=17 July 2026}}</ref>

Back later suggested that Satoshi also examine MicroMint, another micropayment proposal. Their next documented contact was on 10 January 2009, when Satoshi informed Back that the Bitcoin software had been released.<ref name="back-statement" />

The correspondence was made public when Back gave evidence in the 2024 [[wikipedia:Crypto Open Patent Alliance|Crypto Open Patent Alliance]] case concerning Craig Wright's claim to be Satoshi. The High Court judgment described Back's evidence as careful, considered and truthful, and found that the emails contradicted Wright's account of Bitcoin's development.<ref name="copa-judgment" />

==Blockstream and sidechains==
In October 2014, Back was one of nine authors of ''Enabling Blockchain Innovations with Pegged Sidechains''. The paper proposed two-way pegs that would allow bitcoins and other ledger assets to move between separate blockchains, enabling experimentation while attempting to isolate failures from the Bitcoin main chain.<ref name="sidechains">{{cite web|url=https://blockstream.com/sidechains.pdf|title=Enabling Blockchain Innovations with Pegged Sidechains|author=Back, Adam et al.|date=22 October 2014|publisher=Blockstream|accessdate=17 July 2026}}</ref>

In 2014, Back was one of Blockstream's 11 co-founders. The company initially focused on sidechains and other protocol-level extensions to Bitcoin and announced a US$21 million seed round in November 2014.<ref name="seed-round">{{cite web|url=https://blog.blockstream.com/en-blockstream-closes-21m-seed-round/|title=Blockstream closes $21M seed round|publisher=Blockstream|date=17 November 2014|accessdate=17 July 2026}}</ref> Back served as president and chief operating officer before Blockstream appointed him CEO on 3 October 2016.<ref name="blockstream-ceo" />

In a 2014 statement, Back said Blockstream would support decentralisation, end-to-end security, user control and permissionless innovation, and described sidechains as the company's most pressing technical work.<ref>{{cite web|url=https://blog.blockstream.com/en-blockstream-a-champion-of-bitcoins-core-values/|title=Blockstream: A Champion of Bitcoin's Core Values|author=Back, Adam|publisher=Blockstream|date=17 November 2014|accessdate=17 July 2026}}</ref> During the 2017 scaling dispute, he publicly opposed the [[SegWit2x]] hard-fork proposal.<ref>[https://x.com/adam3us/status/913495697936277504 Adam Back on X], 28 September 2017.</ref><ref>[https://old.reddit.com/r/Bitcoin/comments/72ryef/it_is_time_to_call_off_nyasegwit2x_and_work/ “It is time to call off NYA/segwit2x”], Reddit, 27 September 2017.</ref>

==Satoshi identity speculation==
In April 2026, ''The New York Times'' published an investigation claiming that Back was the person behind the Satoshi Nakamoto pseudonym. Back denied being Satoshi and said the similarities cited by the investigation were coincidences among people with similar experience and interests.<ref name="guardian" />

==See also==
* [[wikipedia:Adam Back|Adam Back on Wikipedia]]

==References==
<references />

Adam Back

2026-07-17T09:13:06Z

NotATether: Expand from stub

{{infobox person|name=Adam Back
|image=[[File:Adam Back 2025.png|256px]]
|caption=Adam Back in 2025. Photo by Alexandre Sitter
|knownfor=[[Hashcash]]; co-founding [[Blockstream]]
|notableworks=[[Hashcash]]; ''Enabling Blockchain Innovations with Pegged Sidechains''
}}
'''Adam Back''' is a British computer scientist, cryptographer and cypherpunk who invented [[Hashcash]], a [[proof-of-work]] system announced in 1997 and later cited in the Bitcoin white paper, and co-founded the Bitcoin infrastructure company [[Blockstream]].<ref name="guardian">{{cite web|url=https://www.theguardian.com/technology/2026/apr/08/british-computer-scientist-adam-back-denies-he-is-bitcoin-developer-satoshi-nakamoto|title=British computer scientist denies he is bitcoin developer Satoshi Nakamoto|work=The Guardian|author=Down, Aisha|date=8 April 2026|accessdate=4 July 2026}}</ref><ref name="hashcash-papers">{{cite web|url=http://www.hashcash.org/papers/|title=Hashcash papers|publisher=Hashcash.org|accessdate=17 July 2026}}</ref><ref name="whitepaper">{{cite web|url=https://bitcoin.org/bitcoin.pdf|title=Bitcoin: A Peer-to-Peer Electronic Cash System|author=Nakamoto, Satoshi|date=31 October 2008|accessdate=4 July 2026}}</ref><ref name="blockstream-ceo">{{cite web|url=https://blockstream.com/press-releases/2016-10-03-blockstream-appoints-hashcash-inventor-dr-adam-back-as-ceo/|title=Blockstream Appoints Hashcash Inventor Dr. Adam Back as CEO|publisher=Blockstream|date=3 October 2016|accessdate=4 July 2026}}</ref>

==Background and Hashcash==
Back received a Ph.D. in distributed systems and computer science from the University of Exeter. Before Blockstream, he worked in cryptography, electronic cash and privacy technology and held senior roles at Zero-Knowledge Systems, Microsoft, EMC and VMware; he also co-founded the cloud-infrastructure company Pi Corporation.<ref name="blockstream-ceo" />

Back first announced Hashcash on the cypherpunks mailing list in March 1997. It was designed to deter email spam and denial-of-service attacks by requiring a sender to calculate a proof-of-work stamp that was moderately costly to produce but inexpensive for a recipient to verify. Back described the system formally in his 2002 paper ''Hashcash - A Denial of Service Counter-Measure''.<ref name="hashcash-papers" /><ref name="hashcash-paper">{{cite web|url=http://www.hashcash.org/papers/hashcash.pdf|title=Hashcash - A Denial of Service Counter-Measure|author=Back, Adam|date=1 August 2002|accessdate=17 July 2026}}</ref>

Bitcoin adapted this computational asymmetry for a different purpose. The white paper describes a proof-of-work system similar to Hashcash for Bitcoin's distributed timestamp server: miners repeatedly hash block headers until one satisfies the network target, and the accumulated work helps establish transaction order, resist double-spending and secure the issuance of new coins.<ref name="whitepaper" />

==Correspondence with Satoshi Nakamoto==
On 20 August 2008, [[Satoshi Nakamoto]] emailed Back a pre-release draft then titled ''Electronic Cash Without a Trusted Third Party'' and asked him to verify the citation to the Hashcash paper. Back confirmed the citation on 21 August and pointed Satoshi to Wei Dai's [[b-money]] proposal. Satoshi replied that he had not previously seen the b-money page and then contacted Dai to establish its publication date. The b-money citation became the first reference in the published Bitcoin white paper, while Hashcash appeared as the sixth.<ref name="back-statement">{{cite web|url=https://bitcoindefense.org/assets/documents/First-Witness-Statement-of-Dr-Adam-Back.pdf|title=First Witness Statement of Dr Adam Back|author=Back, Adam|date=17 July 2023|publisher=High Court of Justice|accessdate=17 July 2026}}</ref><ref name="copa-judgment">{{cite web|url=https://www.judiciary.uk/wp-content/uploads/2024/05/COPA-v-Wright-Judgment.pdf|title=Crypto Open Patent Alliance v Craig Steven Wright: Approved Judgment|author=Mellor, James|publisher=High Court of Justice of England and Wales|date=20 May 2024|accessdate=17 July 2026}}</ref>

Back later suggested that Satoshi also examine MicroMint, another micropayment proposal. Their next documented contact was on 10 January 2009, when Satoshi informed Back that the Bitcoin software had been released.<ref name="back-statement" />

The correspondence was made public when Back gave evidence in the 2024 [[wikipedia:Crypto Open Patent Alliance|Crypto Open Patent Alliance]] case concerning Craig Wright's claim to be Satoshi. The High Court judgment described Back's evidence as careful, considered and truthful, and found that the emails contradicted Wright's account of Bitcoin's development.<ref name="copa-judgment" />

==Blockstream and sidechains==
In October 2014, Back was one of nine authors of ''Enabling Blockchain Innovations with Pegged Sidechains''. The paper proposed two-way pegs that would allow bitcoins and other ledger assets to move between separate blockchains, enabling experimentation while attempting to isolate failures from the Bitcoin main chain.<ref name="sidechains">{{cite web|url=https://blockstream.com/sidechains.pdf|title=Enabling Blockchain Innovations with Pegged Sidechains|author=Back, Adam et al.|date=22 October 2014|publisher=Blockstream|accessdate=17 July 2026}}</ref>

In 2014, Back was one of Blockstream's 11 co-founders. The company initially focused on sidechains and other protocol-level extensions to Bitcoin and announced a US$21 million seed round in November 2014.<ref name="seed-round">{{cite web|url=https://blog.blockstream.com/en-blockstream-closes-21m-seed-round/|title=Blockstream closes $21M seed round|publisher=Blockstream|date=17 November 2014|accessdate=17 July 2026}}</ref> Back served as president and chief operating officer before Blockstream appointed him CEO on 3 October 2016.<ref name="blockstream-ceo" />

In a 2014 statement, Back said Blockstream would support decentralisation, end-to-end security, user control and permissionless innovation, and described sidechains as the company's most pressing technical work.<ref>{{cite web|url=https://blog.blockstream.com/en-blockstream-a-champion-of-bitcoins-core-values/|title=Blockstream: A Champion of Bitcoin's Core Values|author=Back, Adam|publisher=Blockstream|date=17 November 2014|accessdate=17 July 2026}}</ref> During the 2017 scaling dispute, he publicly opposed the [[SegWit2x]] hard-fork proposal.<ref>[https://x.com/adam3us/status/913495697936277504 Adam Back on X], 28 September 2017.</ref><ref>[https://old.reddit.com/r/Bitcoin/comments/72ryef/it_is_time_to_call_off_nyasegwit2x_and_work/ “It is time to call off NYA/segwit2x”], Reddit, 27 September 2017.</ref>

==Satoshi identity speculation==
In April 2026, ''The New York Times'' published an investigation claiming that Back was the person behind the Satoshi Nakamoto pseudonym. Back denied being Satoshi and said the similarities cited by the investigation were coincidences among people with similar experience and interests.<ref name="guardian" />

==See also==
* [[wikipedia:Adam Back|Adam Back on Wikipedia]]

==References==
<references />

File:Adam Back 2025.png

2026-07-17T07:57:03Z

NotATether:

== Licensing ==
{{subst:nld}}

Abescrow

2026-07-17T07:17:08Z

NotATether: Update the page

'''ABEscrow''' was an early Bitcoin escrow service operated by Atlantic Escrow Limited in Hong Kong.

==Service model==
ABEscrow held bitcoin during a transaction until the sender released the funds to the recipient after receiving the promised item or service. This was a custodial, third-party escrow model: the operator temporarily controlled the funds and was expected to reduce non-delivery risk between buyers and sellers.

An archived version of the service's homepage from 2 November 2013 marketed ABEscrow as an “Anonymous Bitcoin Escrow,” identified the operator as Atlantic Escrow Limited in Hong Kong, and claimed that the service did not retain IP addresses in its log files.<ref name="archive">{{cite web|url=https://web.archive.org/web/20131102142258/https://abescrow.com/|title=ABEscrow: Anonymous Bitcoin Escrow|publisher=Internet Archive|date=2 November 2013|accessdate=17 July 2026}}</ref>

==See also==
* [[Escrow]]
* [[Secure Trading]]

==External links==
* [https://web.archive.org/web/20131102142258/https://abescrow.com/ Archived ABEscrow website] (2 November 2013)

==References==
<references />

[[Category:Escrow services]]
[[Category:Historical services]]

User:NotATether

2026-07-17T05:43:12Z

NotATether: Moderation Policy

{{infobox company
|bitcointalk=2739424
}}

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, requests to send money to your bitcoin address and so on.

Example of an edit that will be rejected (and will cause you to be marked as a spammer):

<code>
bc1qr9872934yhrw send $500 here
</code>

However, if it is only an address for donations, as long as you have other profile information and a description about yourself, it is fine.

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

Abe

2026-07-16T10:13:19Z

NotATether: Add summary

'''Abe''' is a free, open-source [[block chain browser]] released by [[User:JohnTobey253|John Tobey]] under the [[wikipedia:Affero General Public License|Affero General Public License]].

Written in [[wikipedia:Python (programming language)|Python]] and portable [[wikipedia:SQL|SQL]], Abe drew inspiration from [[Bitcoin Block Explorer]] and sought partial compatibility with it while using a new implementation.<ref>{{cite web|url=https://github.com/bitcoin-abe/bitcoin-abe|title=Abe: a free block chain browser for Bitcoin-based currencies|publisher=GitHub|accessdate=4 July 2026}}</ref>

==History==
John Tobey announced Abe on BitcoinTalk in June 2011 as an AGPL block explorer hosted on GitHub. The announcement described it as free and open source, able to show block, transaction and address-history pages, written in Python and portable SQL, and able to handle several chains in the same database.<ref>{{cite btct|id=16141|title=[update] ABE: AGPL Block Explorer on github|date=13 June 2011}}</ref> A later announcement for Abe 0.7 described it as an open-source blockchain browser with a subset of the Bitcoin Block Explorer interface and API.<ref>{{cite btct|id=22785|title=[ANNOUNCE] Abe 0.7: Open Source Block Explorer Knockoff|date=26 June 2011}}</ref>

==See also==
* [[Block chain browser]]

==External links==
* [https://bitcointalk.org/index.php?topic=22785.0 Project announcement]
* [https://github.com/bitcoin-abe/bitcoin-abe Project on GitHub]

==References==
<references />

[[Category:Block chain browsers]]
[[Category:Free Software]]
[[Category:Open Source]]

A2A Transfer Methods

2026-07-16T08:17:09Z

NotATether: Fix formatting

{{ambox|type=warning|text='''Out of date.''' The services and links below may be defunct, renamed or unrelated to their former operators.}}

This is a directory of sites and services where account-to-account (A2A) transfers are possible.

The following are sites and services where bitcoins may be transferred from one user account to another, internally, without there being an external transaction (e.g., blockchain, bank network, etc.).

Internal transfers are ledger entries maintained by a service operator, not Bitcoin settlement. They depend on the operator honoring account balances and withdrawals. [[Redeemable code|Redeemable codes]] are bearer codes that can be passed from one account holder to another.

== List of sites==

Entries may not be up-to-date. Check if the sites are still working and offering A2A transfer services.

===Bitcoin accounts===
These services advertise internal Bitcoin-denominated transfers.

{| class="wikitable"
! Service
! Website
! Method
! Exchanges
! Notes
|-
| [[Bitstamp]] || [http://www.bitstamp.net Bitstamp.net] || Redeemable code || [[BitInstant]] || Denominated in BTC, USD or a combination of BTC and USD.
|-
| [[BTC-E]] || [http://www.btc-e.com BTC-e] || Redeemable code || [[BitInstant]] (destination) || Denominated in BTC, USD and RUB.
|-
| [[CampBX]] || [http://www.campbx.com CampBX.com] || Transfer || — || BTC transfers to a recipient's CBX Instant Transfer Code.
|-
| [[Coinapult]] || [http://www.coinapult.com Coinapult.com] || Send || — || BTC transfers to an email address or mobile number.
|-
| [[Coinbase]] || [http://www.coinbase.com Coinbase.com] || Send money || — || BTC transfers to an email address.
|-
| MailACoin || [http://www.mailacoin.com MailACoin.com] || Send money || — || BTC transfers to an email address.
|-
| Seals With Clubs poker || [http://sealswithclubs.eu SealsWithClubs.eu] || Transfer || — || Transfer of “Seals Chips” to another username.
|-
| Kate Poker || [https://www.k8poker.net K8Poker.net] || Transfer || — || Transfer of “Kate Poker Chips” to another username.
|}

===Other financial services===

{| class="wikitable"
! Service
! Website
! Method
! Exchanges
! Notes
|-
| Abra || [http://www.goabra.com Abra] || Send money || n/a || Customer-to-customer transfers funded by debit card or cash deposited with a teller; cash withdrawal through a teller.
|-
| T-Mobile || [http://www.t-mobile.com/landing/moneyservices.html Mobile Money from T-Mobile] || Send money || n/a || Customer-to-customer transfers, ATM withdrawals and cash loading at T-Mobile locations.
|-
| [[Dwolla]] || [http://www.dwolla.com Dwolla.com] || Send || n/a || USD transfers to an email address, mobile number or Dwolla account number.
|-
| Square || [http://vimeo.com/53634501 Square Gift Cards] || Gift || n/a || USD gift cards sent by email; limited to U.S. merchants.
|-
| [[LavaPay]] || [http://www.lavapay.com LavaPay.com] || Send money || n/a || USD transfers to an email address or LavaPay Wallet ID; the historical entry also mentioned a Bitcoin wallet.
|-
| [[OKPay]] || [http://www.okpay.com OKPay.com] || Send money || n/a || USD transfers to an email address or OKPay Wallet ID.
|-
| PayM || [http://www.paym.co.uk PayM.com] || Send money || n/a || Transfers to a UK mobile number linked to the recipient's bank account.
|-
| [[PayPal]] || [http://www.paypal.com PayPal.com] || Send money || n/a || Transfers to an email address or mobile number.
|-
| Scottrade || [https://www.scottrade.com/documents/formscenter/LOAT.pdf Scottrade transfer authorization] || Transfer || n/a || Transfer of cash or securities between accounts.
|-
| Schwab || [http://www.schwab.com/public/file/P-221676/Letter_of_Authorization_for_Transfers_Checks_APP13297-09_WB.pdf Schwab transfer letter] || Transfer || n/a || Transfer of cash or securities between accounts.
|-
| [[Payza]] || [http://www.payza.com Payza.com] || Send || n/a || Transfers to an email address in USD, EUR, GBP or CAD.
|-
| [[Pingit]] || [http://www.barclays.co.uk/Mobile/BarclaysPingit/P1242603570446 Barclays Pingit] || Send || [[BlockChain.info]] || GBP transfers to a mobile number or email address.
|-
| [[VirWoX]] || [http://www.virwox.com VirWoX.com] || Send || n/a || Transfers of Second Life Linden dollars to another VirWoX account.
|-
| nTrust || [http://ntrust.com nTrust.com] || Transfer || n/a || Funds could be spent with an nTrust prepaid debit card.
|-
| M-Pesa (Kenya) || [http://www.safaricom.co.ke/personal/m-pesa M-Pesa] || Send || BitPesa.co || Transfers to Safaricom Kenya mobile users.
|}

==See also==
* [[Payment methods]]
* [[Redeemable code]]
* [[Bitcoin Escrow Service]]

==References==
<references />

[[Category:Financial]]
[[Category:Historical pages]]

50Miner

2026-07-16T07:52:50Z

NotATether: Formatting makeover

'''50Miner''' was a Windows graphical frontend for Bitcoin mining software, developed in cooperation with the [[50BTC]] mining pool. It was intended to make early GPU and FPGA mining easier for users who did not want to configure miners from the command line.

==Screenshots==
<gallery widths="220" heights="160">
File:50Miner_screenshot1.png
File:50Miner_screenshot2.png
File:50Miner_screenshot3.png
File:50Miner_screenshot4.png
File:50Miner_screenshot5.png
</gallery>

==Features==
50Miner had the following capabilities:

* Connecting to the 50BTC pool with only a username and password.
* Detecting installed video cards and OpenCL platforms.
* Providing a download link when a required OpenCL platform was missing.
* Starting mining automatically with selected hardware settings.
* An advanced mode for configuring mining settings manually.
* Displaying speed and accepted or rejected shares.
* Instant payments from 50BTC to:
** Bitcoin addresses
** Mobile telephone numbers
** Yandex.Money
** QIWI
** WebMoney (RUB)
** Visa
* Displaying balances for:
** [[50BTC]]
** [https://web.archive.org/web/20121214143943/http://www.abcpool.co/ ABCPool]
** [[Bitclockers]]
** [[BTC Guild]]
** [[BTCMine]]
** [[DeepBit]]
** [[Eclipse Mining Consortium]]
** [[Pool.itzod.ru]]
** [[Pool.mkalinin.ru]]
** [https://web.archive.org/web/20120713021626/https://mtred.com/ Mt.Red]
** [[Ozco.in]]
** [[Bitcoin Pooled Mining]]
** [[Triplemining]]

==Supported miners==
* [[Poclbm]]
* [[Phoenix miner]]
* [[DiabloMiner]]
* [[CGMiner]]

==Supported languages==
* English
* Russian
* German

==Version history==
{| class="wikitable"
! Version
! Release date
! Changes
|-
| 0.5.3
| 12 July 2013
|
* Updated interaction with the [[50BTC]] pool.
* Updated cgminer to version 3.3.1.
|-
| 0.5.2
| 5 April 2013
|
* Displayed the Bitcoin exchange rate using the new Mt. Gox API.
|-
| 0.5.1
| 22 February 2013
|
* Added detailed connection-error information in simple mode.
* Ran cgminer when an FPGA was detected, including on systems without a GPU.
|-
| 0.5.0
| 21 February 2013
|
* Fixed a Windows Server bug.
* Positioned the compact-information window according to the taskbar location.
* Restored the window size used when the application was last closed.
* Fixed a zero payout-destination count.
* Added email notification when the primary pool failed.
* Added support for new and modified language files.
* Corrected display of the graphics-card voltage.
* Fixed a Windows 8 issue following update KB2795944.
|-
| 0.4.2
| 14 December 2012
|
* Corrected FPGA operation.
|-
| 0.4.1
| 21 December 2012
|
* Added mining-aggression controls.
* Allowed selection of the CPU used by the miner.
* Allowed cgminer settings to be specified for Litecoin mining.
* Allowed tabs to be moved and workers to be renamed.
|-
| 0.4.0
| 14 December 2012
|
* Added flexible miner scheduling through Windows Task Scheduler.
|-
| 0.3.0
| 12 November 2012
|
* Fixed an error in the payout-destinations list.
|-
| 0.2.9
| 9 November 2012
|
* Corrected speed and share display for video cards with identical names.
* Expanded the list of basic settings.
|-
| 0.2.8
| 29 October 2012
|
* Fixed a cgminer launch error.
|-
| 0.2.7
| 26 October 2012
|
* Added cgminer support with limited basic settings.
|-
| 0.2.6
| 24 October 2012
|
* Corrected poclbm.exe behavior for aggression values 0–12.
* Fixed layout problems on Windows XP.
* Saved the position of the Overclocking tab.
* Improved operating-system bitness detection.
|-
| 0.2.5
| 2 October 2012
|
* Improved DiabloMiner logging.
|-
| 0.2.4
| 1 October 2012
|
* Added minor fixes related to payout destinations.
|-
| 0.2.3
| 26 September 2012
|
* Fixed errors when reducing ATI/AMD graphics-card core and memory frequencies.
* Improved error logging.
|-
| 0.2.2
| 25 September 2012
|
* Fixed fan and PowerControl handling.
* Fixed the start/stop-all-miners control in simple mode.
|-
| 0.2.1
| 24 September 2012
|
* Fixed termination of java.exe.
* Fixed saved DiabloMiner settings.
* Fixed selection of video cards with identical names.
* Fixed overclocking of ATI/AMD cards with identical names.
|-
| 0.2
| 21 September 2012
|
* Added overclocking controls for ATI/AMD graphics cards.
|-
| 0.1
| 14 September 2012
|
* First release.
|}

==External links==
* [https://web.archive.org/web/20130604123056/http://50miner.org/ Archived 50Miner website] (4 June 2013)
* [https://web.archive.org/web/20130619092330/https://50btc.com/ Archived 50BTC mining pool] (19 June 2013)
* [https://www.bitcoinmining.com/bitcoin-mining-software/ Bitcoin Mining Software]

[[Category:Miners]]
[[Category:Free Software]]
[[Category:Historical software]]

50BTC

2026-07-15T13:22:44Z

NotATether: Expand it, but it's still a stub

'''50BTC''' was a large Bitcoin [[mining pool]]. Its BitcoinTalk announcement advertised pay-per-share (PPS) with a 3% fee, a minimum payout of 0.01 BTC, Stratum support, variable difficulty, and optional mining on port 80.<ref>[https://bitcointalk.org/index.php?topic=54673.0 50BTC.com discussion thread]</ref>

==External links==

* [https://web.archive.org/web/20130619092330/https://50btc.com/ Archived 50BTC website] (19 June 2013)
* [https://bitcointalk.org/index.php?topic=54673.0 bitcointalk.org] Topic on bitcointalk.org

==References==
<references />

[[Category:Mining pools]]
[[Category:Historical pages]]
 {{stub}}

24change

2026-07-15T10:19:25Z

NotATether: Expand page

{{ambox|type=warning|text='''Warning: This exchange has discontinued its services.''' Any acquisition or later use of the domain does not represent the original operators, nor does it verify the historical claims on this page.}}

{{infobox company|industry=[[Fiat exchange]]|foundation=May 2, 2013|pairs=USD/RUB BTC/USD|website=https://24change.com|bitcointalk=80357|bitcoinwiki=24Change}}

'''24change''' was a Bitcoin exchange service announced on 2 May 2013 in a Russian-language BitcoinTalk thread. An English-language thread later advertised support for Bitcoin, Paymer, BTC-e codes, Perfect Money, OKPay, PayPal and C-GOLD.<ref>{{cite btct|id=193434|title=24change launch thread|date=2 May 2013}}</ref><ref>{{cite btct|id=254488|title=24change.com - Buy/Sell Bitcoin, Paymer, BTC-E code, PM, Okpay, Paypal, C-GOLD|date=11 July 2013}}</ref>

In 2014, BitcoinTalk users posted scam warnings and complaints about the service.<ref>{{cite btct|id=686473|title=WARNING SCAM ALERT!!! 24change.com SCAM|date=11 July 2014}}</ref><ref>{{cite btct|id=634785|title=24change a scam?|date=1 June 2014}}</ref>

==References==
<references />
{{article}}
[[Category:Exchanges]]
[[Category:Defunct exchanges]]
[[Category:USD exchanges]]
[[Category:RUB exchanges]]
[[Category:Properties established in 2013]]
[[ru:24change.com]]

User:NotATether

2026-07-15T10:02:55Z

NotATether: add bitcointalk icon

{{infobox company
|bitcointalk=2739424
}}

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.

21bitcoin

2026-07-15T09:58:25Z

NotATether: Expand page

{{infobox company
|foundation=June 2011
|defunct=May 22, 2012
|founder=nakowa
|bitcointalk=14305
}}
:''Not to be confused with [[21]].''

'''21bitcoin''' was an early Hong Kong Bitcoin mining pool and Chinese-language Bitcoin site operated by BitcoinTalk user ''nakowa''.<ref name="nakowa-profile">{{cite web|url=https://bitcointalk.org/index.php?action=profile;u=14305|title=nakowa profile|publisher=BitcoinTalk|accessdate=4 July 2026}}</ref> The pool offered mining contracts, a pool at <code>p.21bitcoin.com</code>, and a site forum.<ref name="archive-pool">{{cite web|url=https://web.archive.org/web/20110607035835/http://21bitcoin.com/mining-pool|title=Archived 21bitcoin mining pool page|publisher=Internet Archive|date=7 June 2011|accessdate=4 July 2026}}</ref><ref name="archive-forum">{{cite web|url=https://web.archive.org/web/20110625150956/http://21bitcoin.com/forum|title=Archived 21bitcoin forum page|publisher=Internet Archive|date=25 June 2011|accessdate=4 July 2026}}</ref>

The operator also offered mining contracts through a forum-based model. A 15 June 2011 BitcoinTalk thread by ''nakowa'' advertised Radeon HD 6990 mining capacity running Ubuntu 11.04 and poclbm.<ref name="contract">{{cite btct|id=17208|title=HK mining contract|date=15 June 2011}}</ref>

It is not known if the pool had ever solved a block. It shut down in 2011, but the site remained as a blog until the domain expired the following year. By 15 June 2012, an archived capture of <code>21bitcoin.com</code> showed a parked-domain page stating that the domain had expired on 22 May 2012.<ref name="archive-expired">{{cite web|url=https://web.archive.org/web/20120615160756/http://21bitcoin.com/|title=Archived 21bitcoin.com parked-domain page|publisher=Internet Archive|date=15 June 2012|accessdate=4 July 2026}}</ref>.

==References==
<references />
{{pools}}
{{article}}
[[Category:Properties established in 2011]]
[[Category:Mining pools]]
[[Category:Defunct mining pools]]
[[Category:Barely notable subjects]]

2011

2026-07-15T09:29:13Z

NotATether: Expand Mt. Gox entry

{{year}}{{Infobox year|year=2011
|firstblock=100410
|blocks=59,626
|supply=5,020,450
|mining=2,981,300
|startdifficulty=14,484
|enddifficulty=1,159,929
|hashrate=
|open=$0.30 USD
|high=$31.91 USD
|low=$0.29 USD
|close=$4.70 USD
|marketcap={{increase}} $23.6 million USD
|blockvalue={{increase}} $235.00 USD
|blockreward=50 BTC
}}'''2011''' was the third year since the launch of [[Bitcoin]]. [[Dollar parity]] was achieved as [[Satoshi Nakamoto]] departed.__TOC__

==Events==
===January===
*02 – [[Luke Dashjr]] standardizes [[Tonal Bitcoin]].
*08 – [[Bitcoin Pooled Mining]] reaches 10 [[hash per second|Ghash/s]].
*28 – [[Block]] 105000 is [[mining|mined]], meaning the supply of bitcoins reaches 25% of its [[controlled supply|target]].
===February===
*09 – Bitcoin achieves [[dollar parity]]. 1 bitcoin trades for 1 US dollar on [[Mt. Gox]].<ref>{{cite web|url=https://news.slashdot.org/story/11/02/10/189246/Online-Only-Currency-BitCoin-Reaches-Dollar-Parity|title=Online-Only Currency BitCoin Reaches Dollar Parity|publisher=Slashdot|date=10 February 2011|accessdate=4 July 2026}}</ref>
*10 – News of dollar parity attracts significant attention; [[bitcoin.org]] struggles to handle the traffic.<ref>{{cite btct|id=3444|title=HUGE spike in Google trends|date=2011-02-13}}</ref>
*14 – For the first time, a vehicle is offered for a sum of bitcoins. It was a 1984 Celica Supra for 3000 BTC.<ref>{{cite btct|id=3485|title=Car for Sale - Australia|date=2011-02-14}}</ref> A buyer was never found.
===March===
*01 – [[Jed McCaleb]] sells [[Mt. Gox]] to [[Mark Karpelès]].
*06 – The network hashrate [[March 6, 2011 hashrate anomaly|briefly doubles]].<ref>[http://bitcoin.atspace.com/mysteryminer.html]</ref>
*18 – BTC/USD exchange rate reaches a 6-week low point at almost $0.70/BTC, after what appeared to be a short burst of possibly automated sales at progressively lower prices. The price had been declining since dollar parity.
*22 – [[WeUseCoins]] publishes ''[[What is Bitcoin?]]'', which became a viral hit.
*25 – [[Difficulty]] decreases for the second time ever.
*27 – [[Britcoin]] is established, opening the first Bitcoin exchange for the Pound Sterling.
*31 – [[Bitcoin Brazil]] is established, opening the first Bitcoin exchange for the Brazilian real.
===April===
*05 – [[Bitmarket.eu]] is established, opening the first Bitcoin exchange for the Polish złoty.
*12 – The first Bitcoin put option contract is sold on [[Bitcoin-OTC]].
*16 – TIME publishes an article on Bitcoin.
*23 – The exchange rate reaches parity with the Euro and Pound Sterling.
*27 – [[VirWoX]] is established, opening the first Bitcoin exchange for the Linden dollar.
*30 – [[Difficulty]] tops 100,000.
===June===
*02 – The [[Mt. Gox]] exchange rate reaches an all-time high of $10.
*08 – The [[2011 bubble]] tops at over $30, and pops in the following week.
*13 – [[allinvain]] reports the theft of 25,000 BTC, worth $375,000.
*19 – [[Mt. Gox]] suffers a major security breach. A compromised auditor account is used to place fraudulent trades, briefly driving the displayed price to one cent. Mt. Gox also disclosed that its user database had leaked.<ref>{{cite news|url=https://www.wired.com/2011/06/gox/|title=Bitcoin Prices Plummet on Hacked Exchange|publisher=Wired|date=19 June 2011|accessdate=4 July 2026}}</ref>
*24 – [[Difficulty]] tops 1,000,000.
==References==
<references/>
{{wp}}

2010

2026-07-15T09:21:17Z

NotATether: Add references and fix broken block reference

<noinclude>{{year}}{{Infobox year|year=2010
|firstblock=32510
|blocks=67920
|supply=1,624,500
|mining=3,396,000
|startdifficulty=1.18
|enddifficulty=14,484
|blockreward=50 BTC
}}'''2010''' was the year after the year of [[Bitcoin]]'s launch.__TOC__
==Events==</noinclude>
===February===
*06 – [[Bitcoin Market]], the first [[exchange]], is launched.
===April===
*14 – [[Martti Malmi]] starts the [[Bitcoin Wiki]].
===May===
*22 – [[Laszlo Hanyecz]], a GPU miner, makes the [[Laszlo Hanyecz#Pizza|first documented purchase of a good in exchange for bitcoins]]; two pizzas for 10,000 BTC.<ref>{{cite btct|id=137|title=Pizza for bitcoins?|date=18 May 2010}}</ref>
===July===
*07 – Bitcoin v0.3 is released.
*11 – News of the latest release propagates to Slashdot, causing a large influx of bitcoin users.<ref>{{cite web|url=https://slashdot.org/story/10/07/11/1747245/bitcoin-releases-version-03|title=Bitcoin Releases Version 0.3|publisher=Slashdot|date=11 July 2010|accessdate=4 July 2026}}</ref>
*12 – Bitcoin value begins rising rapidly, going from $0.008 to $0.08 over the next five days.
*17 – [[Mt. Gox]] is established.
*18 – ArtForz becomes one of the earliest GPU miners.
===August===
*15 – 184 billion bitcoins are [[CVE-2010-5139|created artificially]] in block 74638. 53 blocks into a chain fork, the updated chain overtakes the erroneous one and the fraudulent bitcoins cease to exist.<ref>{{cite web|url=https://nvd.nist.gov/vuln/detail/CVE-2010-5139|title=CVE-2010-5139 Detail|publisher=National Vulnerability Database|accessdate=4 July 2026}}</ref>
===September===
*14 – Block 79764 is the first to be solved with split allocation of the block reward.<ref>{{cite web|url=https://blockstream.info/block/00000000001b816df120f4bdf63efd5d986e80c4dbffcf6ad5e73fba0499926d|title=Bitcoin block 79764|publisher=Blockstream Explorer|date=14 September 2010|accessdate=15 July 2026}}</ref>
*18 – [[Jeff Garzik]] pays [[puddinpop]] 10,000 BTC (~$625) to make their Windows-based CUDA client open source.
*29 – [[kermit]] discovers a glitch that prevents transactions referencing small outputs from being confirmed.
===October===
*01 – The [[poclbm|first public OpenCL miner]] is released.
*07 – The exchange rate begins rising again, from $0.06.
*16 – The earliest documented escrowed transaction occurs between [[nanotube]] and [[Diablo-D3]], with [[User:Theymos|Theymos]] as the escrow.
*28 – The earliest documented short sale occurs between [[nanotube]] and [[kiba]].
===November===
*06 – The market capitalization reaches $1,000,000 as the exchange rate passes $0.50.
===December===
*07 – [[ribuck]] sends 0.42 BTC to [[doublec]] in the first mobile-to-mobile transaction.
*09 – [[Difficulty]] surpasses 10,000.
*09 – The earliest documented sale of a call option contract occurs between [[nanotube]] and [[sgornick]].
*13 – [[Satoshi Nakamoto]] logs out of [[BitcoinTalk]] for the last time.
*15 – The [[Bitcoin Wiki]] is reestablished by [[Mark Karpelès]] using MediaWiki.
*16 – The earliest documented pool-mined block is solved by [[Bitcoin Pooled Mining]], aka Slush's Pool.
<noinclude>==References==
<references/>
{{wp}}</noinclude>

0.1.0

2026-07-15T09:02:07Z

NotATether: Expand page

{{infobox Core release
|name=Bitcoin 0.1.0
|image=[[File:screen3.png|256px]]
|caption=Bitcoin client screenshot
|lead=[[Satoshi Nakamoto]]
|contributors=[[Hal Finney]]
|released=January 8, 2009
|os=Windows
|next=0.1.1
}}'''Bitcoin 0.1.0''' was the first public release of the Bitcoin [[client]]. [[Satoshi Nakamoto]] announced it on the Cryptography Mailing List on 8 January 2009 as Windows-only open-source C++ software.<ref name="release">{{cite web|url=https://satoshi.nakamotoinstitute.org/emails/cryptography/16/|title=Bitcoin v0.1 released|author=Nakamoto, Satoshi|publisher=Satoshi Nakamoto Institute|date=8 January 2009|accessdate=4 July 2026}}</ref>

[[Hal Finney]] tested the software shortly after release and helped Satoshi debug early crash and networking problems.<ref name="finney-emails">{{cite web|url=https://www.wsj.com/public/resources/documents/finneynakamotoemails.pdf|title=Emails between Satoshi Nakamoto and Hal Finney|publisher=The Wall Street Journal|date=2014|accessdate=4 July 2026}}</ref>

==References==
<references />

Blocktrail

2026-07-08T06:02:48Z

NotATether: Fix code formatting

{{infobox company|image=[[Image:Blocktrail-logo-black.png|250px]]|name=Blocktrail B.V.
|founder=Boaz Bechar, Ruben de Vries, Jop Hartog
|foundation=March 1, 2014<ref>http://www.coindesk.com/russian-tech-magnates-first-bitcoin-project-launches-beta/</ref>
|industry=[[Wallet]] [[Api]] [[Block Explorer]]
|website=https://www.blocktrail.com
}}[https://www.blocktrail.com Blocktrail] provides a mobile wallet [https://play.google.com/store/apps/details?id=com.blocktrail.mywallet&hl=en '''Android Wallet'''] [https://itunes.apple.com/us/app/blocktrail-bitcoin-wallet/id1019614423/ '''iOS Wallet'''], Bitcoin API, developers platform, and a popular [http://www.blocktrail.com/BTC block explorer] for Bitcoin.

On July 19, 2016 Blocktrail was acquired by [[Bitmain]] and subsequently has re-branded to [[BTC.com]].<ref>http://www.coindesk.com/bitcoin-miner-bitmain-acquires-blockchain-data-startup/</ref>

==Wallet==
Blocktrail's Bitcoin wallet features unparalleled security through Multi-Signature technology, keeping you in full control of your coins at all time. Transactions are signed on your device so we never see your private keys.
With our HD wallets you can create an unlimited number of addresses to help protect your privacy without the need for multiple private key backups. Our system will also generate new addresses for change and fund requests automatically.

Access your wallet anywhere, anytime; use the mobile app when you're on the go, or log in to the web-interface when at home or in the office.

* 2-of-3 Multisig technology so you always remain in control of your coins
* HD wallet technology allowing you to create an unlimited number of addresses
* Send and Receive bitcoin easily with contacts on your phone
* Live update for new transactions and your balance
* View your full transaction history with the price at the time of the transaction
* Personalise your account so your friends can quickly identify you
* QR code scanning with bitcoin URI support
* Send requests via email and SMS
* PIN protection
* Anonymous accounts, for your privacy
* Transactions signed locally on your device
* Backup document incase the worst happens
* Local currency display using live price updates

'''Open Source and available for review on Github:''' http://github.com/blocktrail/blocktrail-wallet

[https://www.blocktrail.com/ '''Web Wallet''']
[https://play.google.com/store/apps/details?id=com.blocktrail.mywallet/ '''Android Wallet''']
[https://itunes.apple.com/us/app/blocktrail-bitcoin-wallet/id1019614423/ '''iOS Wallet''']

== Block Explorer ==
View realtime & historical data on bitcoin addresses, transactions and economy.

* '''Block Size Vote''' - Stay up to date with current block size votes.
* '''Time-based balance analysis''' - Get usage information based on selectable time periods
* '''Mentions''' - Easily see if your searched address appears in any third-party data source
* '''Address Tags''' - Quickly determine if the address was involved in known transactions (gambling, donations, etc).
* '''Search via QR''' - Search any QR code in one click, directly from our homepage
* '''Bookmarks & Lists''' - Easily bookmark addresses and add them to lists for grouped summaries of transactions and balances.

[https://www.blocktrail.com/BTC '''Blocktrail Block Explorer''']

== Bitcoin API and Developers Platform ==
Blocktrail provides secure bitcoin infrastructure for developers and enterprises, enabling advanced transaction functionality and access to refined economic data-sets. Blocktrail's RESTful HTTP API is free-to-use under rate-limited conditions (1 request per second).

* '''Secure Bitcoin Transactions''' - Easily create secure transactions without giving up access to your Bitcoins, using a multi-signature [[Deterministic wallet | HD wallet]] API
* '''Blockchain Data and Insights''' - Refined data on transactions, addresses, and economy analytics delivered via queries, webhooks or firehose
* '''Developer friendly''' - Blocktrail comes complete with SDK's for PHP, Python, NodeJS and more!

[https://www.blocktrail.com/api/docs '''Blocktrail Bitcoin API''']

==Examples==
==== Get Bitcoin Address ====

$ curl "https://api.blocktrail.com/v1/btc/address/1NcXPMRaanz43b1kokpPuYDdk6GGDvxT2T?api_key=MY_APIKEY"

{
"address": "1NcXPMRaanz43b1kokpPuYDdk6GGDvxT2T",
"hash160": "ED12908714FFD43142BF9832692017E8AD54E9A8",
"balance": 49497392,
"received": 115015000,
"sent": 65517608,
"unconfirmed_received": 0,
"unconfirmed_sent": 0,
"unconfirmed_transactions": 0,
"total_transactions_in": 4,
"total_transactions_out": 10,
"category": "donations",
"tag": "blocktrail"
}
</code>

==== Get Latest Block ====

$ curl "https://api.blocktrail.com/v1/btc/block/latest?api_key=MY_APIKEY"

{
"hash": "000000000000000005afebaa75ff40714a1ed96539adb1266bbf7be9aaf767ae",
"height": "321129",
"block_time": "2014-09-17T09:00:26+0000",
"difficulty": "29829733124.00000000",
"merkleroot": "aaadea1a8c2cb1777d822d47e6acd0360b2f2e4f3c7c1f79cb4284866457ade3",
"prev_block": "000000000000000019bea784e37fe450d522b9a4f0a4e8dcad4bd7c9283e4203",
"next_block": null,
"byte_size": "670679",
"confirmations": 1,
"transactions": "727",
"value": "277325560913",
"miningpool_name": "Eligius",
"miningpool_url": "http://eligius.st",
"miningpool_slug": "eligius"
}

==See Also==

* [[Block chain browser]]

==External Links==
* [https://www.blocktrail.com Home page]
* [https://www.blocktrail.com/BTC Block Chain Browser]
* [https://www.twitter.com/blocktrail Follow @blocktrail on twitter]
* [https://bitcointalk.org/index.php?topic=756279.0 Bitcointalk thread]
* [https://www.blocktrail.com/api/docs API Documentation]

==References==
<references />

[[Category:Services]]
[[Category:Wallets]]
[[Category:Mobile]]
[[Category:Block chain browsers]]
[[Category:Frontends]]
[[Category:Bitcoin]]
[[Category:Clients]]

Talk:Block 9

2026-07-07T10:12:16Z

NotATether: merge?

== Merge with Genesis_block? ==

This is a stub and it should probably be merged into some other page. The two that stand out to me are [[block]] and [[Genesis_block | Genesis block]].

--[[User:NotATether|NotATether]] ([[User talk:NotATether|talk]]) 10:12, 7 July 2026 (UTC)

Zulfikar Ramzan

2026-07-07T09:57:52Z

NotATether: It's 9 videos not 8

'''Zulfikar Ramzan''' is a computer-security researcher and technology executive whose Bitcoin-related work includes teaching the [[Bitcoin Video Series (Khan Academy)|Khan Academy Bitcoin Video Series]], a nine-part introduction to Bitcoin and its cryptographic building blocks.<ref name="BitcoinVideoSeries">{{cite web|url=https://en.bitcoin.it/wiki/Bitcoin_Video_Series_(Khan_Academy)|title=Bitcoin Video Series (Khan Academy)|publisher=Bitcoin Wiki|accessdate=7 July 2026}}</ref>

He currently works at Point Wild as its Chief AI & Technology Officer.<ref name="PointWildTeam">{{cite web|url=https://www.pointwild.com/our-team/|title=Our Team|publisher=Point Wild|accessdate=7 July 2026}}</ref>

==Career==

Ramzan's work has focused on cryptography, cybersecurity, malware, fraud, identity, large-scale security analytics, and AI-driven security products. He was a technical director in Symantec's Security Technology and Response division, then held senior technical roles at Immunet, Sourcefire, Elastica, RSA, NetWitness, and Aura.<ref name="BrownProfile">{{cite web|url=https://professional.brown.edu/people/zulfikar-ramzan|title=Zulfikar Ramzan|publisher=Brown University School of Professional Studies|accessdate=7 July 2026}}</ref><ref name="AuraPR">{{cite web|url=https://www.prnewswire.com/news-releases/former-rsa-chief-technology-officer-zulfikar-ramzan-joins-aura-as-chief-scientist-301464393.html|title=Former RSA Chief Technology Officer Zulfikar Ramzan Joins Aura as Chief Scientist|publisher=PR Newswire|date=20 January 2022|accessdate=7 July 2026}}</ref>

At RSA, Ramzan served as Chief Technology Officer and later Chief Digital Officer. He was also Chief Product Officer of NetWitness, RSA's threat detection and response business. In January 2022, Aura announced that he had joined the company as Chief Scientist and CEO of Aura Labs, after having previously served on Aura's board of directors.<ref name="AuraPR" />

==Education and writing==

Ramzan holds a PhD in electrical engineering and computer science from the Massachusetts Institute of Technology, where his doctoral advisor was Ronald L. Rivest.<ref name="BrownProfile" />

He has co-authored more than 50 technical articles and two books, including ''Crimeware: Understanding New Attacks and Defenses''. Brown University's profile credits him with more than 50 granted patents and notes that he served as general chair of Crypto 2010.<ref name="BrownProfile" />

==Bitcoin-related work==

Ramzan has produced the Khan Academy Bitcoin Video Series and served as guest faculty for them.<ref name="BrownProfile" />

==External links==

* [https://www.khanacademy.org/economics-finance-domain/core-finance/money-and-banking/bitcoin Khan Academy Bitcoin videos]
* [https://www.youtube.com/watch?v=EA0LkCkvUeU&list=PL-edc4nsbneXdabCsAExZdbLrvDQGQ6jD YouTube playlist of the Bitcoin series]

==References==

<references />

Bitcoin Video Series (Khan Academy)

2026-07-07T09:55:45Z

NotATether: expand bitcoin video series

'''Bitcoin Video Series (Khan Academy)''' is a set of Khan Academy videos taught by [[Zulfikar Ramzan]] that introduces Bitcoin through its basic technical building blocks: cryptographic hashes, digital signatures, transactions, proof of work, block chains, money supply, and block-chain security.

It currently lists nine videos, all first published in May 2013.<ref name="YouTubeFeed">{{cite web|url=https://www.youtube.com/feeds/videos.xml?playlist_id=PL-edc4nsbneXdabCsAExZdbLrvDQGQ6jD|title=Khan Academy Bitcoin 9-part Series by Zulfikar Ramzan|publisher=YouTube|accessdate=7 July 2026}}</ref>

==Scope==

The series is a short conceptual introduction rather than a wallet, node, exchange, or mining setup guide. Its emphasis is on explaining why Bitcoin uses cryptographic primitives and how those pieces fit together into a transaction ledger. Although it was published in 2013, it is still a valuable resource for those who wish to learn more about how Bitcoin works.

==Videos==

The current YouTube playlist feed lists the following videos:<ref name="YouTubeFeed" />

* [https://www.youtube.com/watch?v=EA0LkCkvUeU Bitcoin: What is it?]
* [https://www.youtube.com/watch?v=Y-w7SnQWwVA Bitcoin: Overview]
* [https://www.youtube.com/watch?v=0WiTaBI82Mc Bitcoin - Cryptographic hash function]
* [https://www.youtube.com/watch?v=Aq3a-_O2NcI Bitcoin - Digital Signatures]
* [https://www.youtube.com/watch?v=9-9_v1wSPBQ Bitcoin - Transaction records]
* [https://www.youtube.com/watch?v=9V1bipPkCTU Bitcoin - Proof of work]
* [https://www.youtube.com/watch?v=QzDO44oZWtE Bitcoin - Transaction block chains]
* [https://www.youtube.com/watch?v=JuWYLAtz3Y4 Bitcoin - The money supply]
* [https://www.youtube.com/watch?v=8zgvzmKZ5vo Bitcoin - The security of transaction block chains]

==See also==

* [[Zulfikar Ramzan]]
* [[How bitcoin works]]
* [[Block chain]]
* [[Proof of work]]
* [[Mining]]

==External links==

* [https://www.khanacademy.org/economics-finance-domain/core-finance/money-and-banking/bitcoin Bitcoin videos on Khan Academy]
* [https://www.youtube.com/watch?v=EA0LkCkvUeU&list=PL-edc4nsbneXdabCsAExZdbLrvDQGQ6jD YouTube playlist]

==References==

<references />

[[Category:Educational]]

Zulfikar Ramzan

2026-07-07T09:47:36Z

NotATether: Remove the stub

'''Zulfikar Ramzan''' is a computer-security researcher and technology executive whose Bitcoin-related work includes teaching the [[Bitcoin Video Series (Khan Academy)|Khan Academy Bitcoin Video Series]], an eight-part introduction to Bitcoin and its cryptographic building blocks.<ref name="BitcoinVideoSeries">{{cite web|url=https://en.bitcoin.it/wiki/Bitcoin_Video_Series_(Khan_Academy)|title=Bitcoin Video Series (Khan Academy)|publisher=Bitcoin Wiki|accessdate=7 July 2026}}</ref>

He currently works at Point Wild as its Chief AI & Technology Officer.<ref name="PointWildTeam">{{cite web|url=https://www.pointwild.com/our-team/|title=Our Team|publisher=Point Wild|accessdate=7 July 2026}}</ref>

==Career==

Ramzan's work has focused on cryptography, cybersecurity, malware, fraud, identity, large-scale security analytics, and AI-driven security products. He was a technical director in Symantec's Security Technology and Response division, then held senior technical roles at Immunet, Sourcefire, Elastica, RSA, NetWitness, and Aura.<ref name="BrownProfile">{{cite web|url=https://professional.brown.edu/people/zulfikar-ramzan|title=Zulfikar Ramzan|publisher=Brown University School of Professional Studies|accessdate=7 July 2026}}</ref><ref name="AuraPR">{{cite web|url=https://www.prnewswire.com/news-releases/former-rsa-chief-technology-officer-zulfikar-ramzan-joins-aura-as-chief-scientist-301464393.html|title=Former RSA Chief Technology Officer Zulfikar Ramzan Joins Aura as Chief Scientist|publisher=PR Newswire|date=20 January 2022|accessdate=7 July 2026}}</ref>

At RSA, Ramzan served as Chief Technology Officer and later Chief Digital Officer. He was also Chief Product Officer of NetWitness, RSA's threat detection and response business. In January 2022, Aura announced that he had joined the company as Chief Scientist and CEO of Aura Labs, after having previously served on Aura's board of directors.<ref name="AuraPR" />

==Education and writing==

Ramzan holds a PhD in electrical engineering and computer science from the Massachusetts Institute of Technology, where his doctoral advisor was Ronald L. Rivest.<ref name="BrownProfile" />

He has co-authored more than 50 technical articles and two books, including ''Crimeware: Understanding New Attacks and Defenses''. Brown University's profile credits him with more than 50 granted patents and notes that he served as general chair of Crypto 2010.<ref name="BrownProfile" />

==Bitcoin-related work==

Ramzan has produced the Khan Academy Bitcoin Video Series and served as guest faculty for them.<ref name="BrownProfile" />

==External links==

* [https://www.khanacademy.org/economics-finance-domain/core-finance/money-and-banking/bitcoin Khan Academy Bitcoin videos]
* [https://www.youtube.com/watch?v=EA0LkCkvUeU&list=PL-edc4nsbneXdabCsAExZdbLrvDQGQ6jD YouTube playlist of the Bitcoin series]

==References==

<references />

Bits of Gold

2026-07-07T09:23:50Z

NotATether: Add licensing information and fix the image

[[File:Bits_of_Gold.png|right]]
'''Bits of Gold''' is an Israeli cryptocurrency trading company. It is a Tel Aviv-registered company providing ILS/BTC exchange services for a fee.

== Services ==

'''Bits of Gold''' lets its users to send their money from all over the world and exchange it for [[Bitcoin|bitcoins]].

Money forwarding is made through means of regular interbank transfers and can also be expedited through the use of IBAN transfers.

The company cooperates with [[BitStamp]] for all USD/BTC exchange purposes and with [[MyWallet]] to create wallets for users which don't provide their own ones.

The current official site describes Bits of Gold as a crypto trading app and platform offering buying, selling and storing cryptocurrency, recurring orders, custody, Bitcoin cashback and business API services.<ref>[https://www.bitsofgold.co.il/en Bits of Gold]</ref> Its regulation page says the company is licensed by Israel's Capital Market, Insurance and Savings Authority under license number 56716 and describes it as the first Israeli crypto company with a permanent financial-services license.<ref>[https://www.bitsofgold.co.il/en/regulation Bits of Gold regulation]</ref>

==See also==
* [[Exchanges]]

==External links==
* [https://www.bitsofgold.co.il/en Bits of Gold]

==References==
<references />

[[Category:Exchanges]]
[[Category:Companies]]

File:Bits of Gold.png

2026-07-07T09:23:15Z

NotATether: Bits of Gold company logo

== Summary ==
Bits of Gold company logo

Bitcoin Express

2026-07-03T07:25:38Z

NotATether: update Bitcoin Express

Bitcoin Express ( BTC Express ) was an iOS thin client for Bitcoin transactions.

Bitcoin Express connected users to the bitcoin network quickly without downloading any blocks or headers. Once connected, you could do transactions immediately.

The project was announced on July 24, 2011<ref>[https://bitcointalk.org/index.php?topic=31362.0 BTC Express -- an iOS thin client for bitcoin - Bitcointalk]</ref>.

Although the app was submitted, it was ultimately not listed on the App Store because the submission was rejected by Apple, who said that the bitcoin-related functions are not legal in all locations where the app is available.<ref>[https://bitcointalk.org/index.php?topic=31362.msg485290#msg485290 Re: Bitcoin Express -- an iOS thin client for bitcoin - Bitcointalk]</ref>

Users have reported that the app was not working as early as September 28, 2011, when the relay server stopped being accessible.<ref>[https://bitcointalk.org/index.php?topic=31362.msg548280#msg548280 Re: Bitcoin Express -- an iOS thin client for bitcoin - Bitcointalk]</ref>

==Features==

* Quickly and easily get up and running on bitcoin network.
* Show balance of btc in your wallet on iPhone.
* Do transactions with any other peer running Mac, Windows or Linux, etc.
* Sending and receiving of Bitcoin via Bitcoin URLs.
* Backup your wallet to your secure email.

==Getting Started==

Note: Because the app is no longer working, this section is kept for historical purposes only.

* Email your recieving address to others

Click and enter "My Address", choose a btc address as your recieving address, touch it. Click "email" on the popup menu, then send the recieving address to others via your Email.

* Send btc to others via Bitcoin Address URL

When you received an email contains a Bitcoin Address URL, by just clicking the URL, BTC Express will automatically open and prepare to send btc to that address.

==See also==
* [[BitcoinApp]]
* [[Mobile Payment Apps]]

==External links==
* [https://github.com/fingster/BTC-Express BTC Express source code on GitHub]
* [http://www.bitcoinexpress.net Historical Bitcoin Express homepage]

==References==
<references />

[[Category:Mobile]]
[[Category:Clients]]
[[Category:Frontends]]
[[Category:Open Source]]
[[Category:Historical software]]

NamecoinUs

2026-07-02T09:56:19Z

NotATether: Added wiki metadata

NamecoinUs! was a project intended to bridge [[namecoin]] domains to common users that do not have the .bit available by their default DNS provider. The project also ran an in-line proxy (http://example.bit => http://example.bit.namecoin.us), a namecoin WHOIS server, and an expiry tracker for namecoin domains. It also offered various namecoin-related tools.

==Current status==
<code>namecoin.us</code> appears to be offline. The domain was seen listed for sale on GoDaddy.

==See also==
* [[Namecoin]]

==External links==
* [http://namecoin.us/ Historical NamecoinUs! project website]
* [https://www.namecoin.org/ Current Namecoin project website]

==References==
<references />

[[Category:Namecoin]]
[[Category:Obsolete]]

Java Bitcoin Client

2026-07-02T09:41:07Z

NotATether: tense

'''Java Bitcoin Client''' is an early Java Bitcoin API project on SourceForge, and is related to Java Bitcoin tooling such as [[BitCoinJ|bitcoinj]] and [[Bitcoin-JSON-RPC-Client]].

==Project record==
The SourceForge project page identifies the project as '''Java Bitcoin API''', a Java API for accessing <code>bitcoind</code>. SourceForge lists it as beta software, licensed under the Apache Software License, registered on 30 September 2010, and last updated on 23 August 2015.<ref>{{cite web|url=https://sourceforge.net/projects/bitcoin-client/|title=Java Bitcoin API|publisher=SourceForge|accessdate=2 July 2026}}</ref>

==Relation to BitcoinJ==
The related [[BitCoinJ|bitcoinj]] project remains the better-known Java Bitcoin protocol library. Its current repository describes bitcoinj as a Java implementation of the Bitcoin protocol that can maintain a wallet and send or receive transactions without requiring a local copy of Bitcoin Core.<ref>{{cite web|url=https://github.com/bitcoinj/bitcoinj|title=bitcoinj/bitcoinj|publisher=GitHub|accessdate=2 July 2026}}</ref>

==See also==
* [[BitCoinJ|bitcoinj]]
* [[Bitcoin-JSON-RPC-Client]]
* [[API reference (JSON-RPC)]]

==External links==
* [http://sourceforge.net/projects/bitcoin-client/ Java Bitcoin API on SourceForge]

==References==
<references />

[[Category:API Bindings]]
[[Category:Frontends]]
[[Category:Free Software]]
[[Category:License/Apache]]
[[Category:Open Source]]
[[Category:Historical software]]

Java Bitcoin Client

2026-07-02T09:40:47Z

NotATether: minor wording fix

'''Java Bitcoin Client''' was an early Java Bitcoin API project on SourceForge, and is related to Java Bitcoin tooling such as [[BitCoinJ|bitcoinj]] and [[Bitcoin-JSON-RPC-Client]].

==Project record==
The SourceForge project page identifies the project as '''Java Bitcoin API''', a Java API for accessing <code>bitcoind</code>. SourceForge lists it as beta software, licensed under the Apache Software License, registered on 30 September 2010, and last updated on 23 August 2015.<ref>{{cite web|url=https://sourceforge.net/projects/bitcoin-client/|title=Java Bitcoin API|publisher=SourceForge|accessdate=2 July 2026}}</ref>

==Relation to BitcoinJ==
The related [[BitCoinJ|bitcoinj]] project remains the better-known Java Bitcoin protocol library. Its current repository describes bitcoinj as a Java implementation of the Bitcoin protocol that can maintain a wallet and send or receive transactions without requiring a local copy of Bitcoin Core.<ref>{{cite web|url=https://github.com/bitcoinj/bitcoinj|title=bitcoinj/bitcoinj|publisher=GitHub|accessdate=2 July 2026}}</ref>

==See also==
* [[BitCoinJ|bitcoinj]]
* [[Bitcoin-JSON-RPC-Client]]
* [[API reference (JSON-RPC)]]

==External links==
* [http://sourceforge.net/projects/bitcoin-client/ Java Bitcoin API on SourceForge]

==References==
<references />

[[Category:API Bindings]]
[[Category:Frontends]]
[[Category:Free Software]]
[[Category:License/Apache]]
[[Category:Open Source]]
[[Category:Historical software]]

Java Bitcoin Client

2026-07-02T09:39:06Z

NotATether: Expand the stub

'''Java Bitcoin Client''' was an early Java Bitcoin API project. The saved article pointed to a SourceForge project and to related Java Bitcoin tooling such as [[BitCoinJ|bitcoinj]] and [[Bitcoin-JSON-RPC-Client]].

==Project record==
The SourceForge project page identifies the project as '''Java Bitcoin API''', a Java API for accessing <code>bitcoind</code>. SourceForge lists it as beta software, licensed under the Apache Software License, registered on 30 September 2010, and last updated on 23 August 2015.<ref>{{cite web|url=https://sourceforge.net/projects/bitcoin-client/|title=Java Bitcoin API|publisher=SourceForge|accessdate=2 July 2026}}</ref>

==Relation to BitcoinJ==
The related [[BitCoinJ|bitcoinj]] project remains the better-known Java Bitcoin protocol library. Its current repository describes bitcoinj as a Java implementation of the Bitcoin protocol that can maintain a wallet and send or receive transactions without requiring a local copy of Bitcoin Core.<ref>{{cite web|url=https://github.com/bitcoinj/bitcoinj|title=bitcoinj/bitcoinj|publisher=GitHub|accessdate=2 July 2026}}</ref>

==See also==
* [[BitCoinJ|bitcoinj]]
* [[Bitcoin-JSON-RPC-Client]]
* [[API reference (JSON-RPC)]]

==External links==
* [http://sourceforge.net/projects/bitcoin-client/ Java Bitcoin API on SourceForge]

==References==
<references />

[[Category:API Bindings]]
[[Category:Frontends]]
[[Category:Free Software]]
[[Category:License/Apache]]
[[Category:Open Source]]
[[Category:Historical software]]

Crypto News 24/7

2026-07-02T09:27:10Z

NotATether: mark offline

{{infobox company
|name=24/7 Crypto News
|image=[[File:247cryptonews-logo2.png|200px]]
|industry=News
|founder=[[Paun Gabriel Razvan]]
|foundation=May 23, 2014
|website=http://247cryptonews.com/
}}

'''24/7 Crypto News''' was a cryptocurrency news site founded on 23 May 2014. It was a startup news agency covering Bitcoin, cryptocurrency security updates, scams and gaps in cryptocurrency news coverage.

==Status==
The currently visible website appeared to have been abandoned - its homepage shows "No content available", category pages like Bitcoin/Ethereum/Solana/Crypto Regulation, and a footer copyright of 2025.<ref>{{cite web|url=https://web.archive.org/web/20251223125056/https://247cryptonews.com/|title=247CryptoNews|publisher=Wayback Machine|accessdate=2 July 2026}}</ref> It is currently offline.

==External links==
* [http://247cryptonews.com/ 24/7 Crypto News]

==References==

[[Category:News services]]
[[Category:Historical publications]]

McxNOW

2026-07-02T09:07:18Z

NotATether: pedantic: remove double newlines

'''McxNOW''' was a digital currency exchange allowing trading of bitcoin and altcoin digital currencies.

The site went into a maintenance period beginning November 15 2014, which according to the site operator took several weeks and destroyed any coins that are not withdrawn by that date. Wallet data was also deleted<ref>[https://mcxnow.com mcxNOW Exchange]</ref>.

==Features==
* Written entirely in C++ for speed and response.<ref>[https://mcxnow.com mcxNOW Exchange]</ref>.
* No internet access to database for security.
* 25% of all mcxNOW exchange fees go towards paying interest on deposits every 6 hours. No trading is required to earn interest payments<ref>[https://mcxnow.com/features.html mcxNOW Exchange Features and FAQ]</ref>.

===Trading===

====Fixed-point integer math trading engine====
mcxNOW uses integers through the entire trade pipeline to ensure you aren't losing out and get precise results.

====Anonymous Trading====
No personal identification required.

====Currency pairs====
* BTC/[[LTC]]
* BTC/MNV
* BTC/[[DVC]]
* BTC/WDC
* BTC/CL
* BTC/XPM
* BTC/SC
* BTC/PPC
* BTC/FTC

====Trading Fees====
There is a 0.2% fee for each side of every trade, so 0.2% for the buyer (BTC fee) and 0.2% for the seller (altcoin fee).

===Deposits===
====Deposit Fees====
There are no fees on bitcoin or alt-coin deposits.
====Deposit Options====
You may deposit any of the following:
*Bitcoin
*[[Litecoin]]
*PrimeCoin
*PeerCoin
*Feathercoin
*MinCoin
*SolidCoin
*[[Devcoin]]
*WorldCoin
*CopperLark

===Withdraws===
====Withdraw Options and Fees====
*Bitcoin (Withdrawal Fee: 0.001BTC)
*Litecoin (Withdrawal Fee: 0.02LTC)
*PrimeCoin (Withdrawal Fee: 0.1MNC)
*PeerCoin (Withdrawal Fee: 0.1PPC)
*Feathercoin (Withdrawal Fee: 0.1FTC)
*MinCoin (Withdrawal Fee: 0.1MNC)
*SolidCoin (Withdrawal Fee: 0.4SC)
*Devcoin (Withdrawal Fee: 50.0DVC)
*WorldCoin (Withdrawal Fee: 0.4WDC)
*CopperLark (Withdrawal Fee: 0.4CL)

==References==
<references />

[[Category:Defunct exchanges]]
[[Category:EWallets]]

McxNOW

2026-07-02T09:06:53Z

NotATether: pedantic: remove double newlines

McxNOW

2026-07-02T09:04:40Z

NotATether: Already defunct

Pycoin

2026-07-02T08:59:19Z

NotATether: Update the page

'''Pycoin''' was an early Python 3 Bitcoin [[client]] and partial Bitcoin protocol implementation. It was a library that implemented parts of the Bitcoin network protocol.

==History==
The project was announced on 3 March 2011 in a BitcoinTalk thread titled "Announcing Pycoin, a (partial) bitcoin protocol implementation in python3".<ref>[https://bitcointalk.org/index.php?topic=4084.0 Announcing Pycoin, a (partial) bitcoin protocol implementation in python3]</ref> The archived page linked to a Gitorious project page.<ref>{{cite web|url=https://en.bitcoin.it/wiki/Pycoin|title=Pycoin|publisher=Bitcoin Wiki|accessdate=2 July 2026}}</ref>

==Name collision==
This historical Pycoin page should not be confused without verification with later Python projects using the same or similar name. For example, the currently maintained <code>richardkiss/pycoin</code> project describes itself as a Python-based Bitcoin and alt-coin utility library, not as the 2011 Gitorious-hosted client described by this article.<ref>{{cite web|url=https://github.com/richardkiss/pycoin|title=richardkiss/pycoin|publisher=GitHub|accessdate=2 July 2026}}</ref>

==See also==
* [[Original Bitcoin client]]
* [[Protocol specification|Bitcoin Network Protocol]]

==External links==
* [http://gitorious.org/pycoin pycoin project page on Gitorious]

==References==
<references />

[[Category:Nodes]]
[[Category:Wallets]]
[[Category:Open Source]]
[[Category:Clients]]
[[Category:Historical software]]

OpenCL miner

2026-06-23T11:56:03Z

NotATether: Rewrite page and update legacy bitcoin.org/smf links

An '''OpenCL miner''' is a Bitcoin mining program that uses the OpenCL computing framework to perform SHA-256 hashing on GPUs or other OpenCL-compatible hardware.

==Role in Bitcoin mining==

OpenCL miners were important during the GPU mining era. GPUs were once much faster than CPUs for Bitcoin hashing, and OpenCL made it possible to use compatible AMD/ATI and other devices for mining.

General-purpose CPU and GPU mining is no longer practical for ordinary Bitcoin mainnet mining. The Bitcoin network's mining difficulty and hardware market are dominated by specialized SHA-256 mining hardware. OpenCL mining remains useful for understanding Bitcoin mining history, GPU hashing implementations, and some non-Bitcoin proof-of-work systems.

Modern mining software and pool infrastructure use newer interfaces than the early <code>getwork</code> and RPC-miner workflows. Bitcoin Core's current mining RPC documentation lists <code>getblocktemplate</code>, <code>getmininginfo</code>, <code>getnetworkhashps</code>, <code>submitblock</code>, and related RPCs.<ref>{{cite web|url=https://bitcoincore.org/en/doc/31.0.0/rpc/mining/getblocktemplate/|title=getblocktemplate (31.0.0 RPC)|publisher=Bitcoin Core|accessdate=23 June 2026}}</ref><ref>{{cite web|url=https://bitcoincore.org/en/doc/31.0.0/rpc/mining/getmininginfo/|title=getmininginfo (31.0.0 RPC)|publisher=Bitcoin Core|accessdate=23 June 2026}}</ref>

==Requirements==

Hashing on a GPU requires an OpenCL compatible ([http://developer.amd.com/gpu/AMDAPPSDK/pages/DriverCompatibility.aspx ATI/AMD]) or CUDA compatible ([http://www.nvidia.com/object/cuda_gpus.html NVIDIA]) graphics card.

The python [[Poclbm]] open source OpenCL bitcoin miner was created by m0mchil<ref>[http://www.bitcointalk.org/index.php?topic=1334.0 m0mchil's announcement on the forum]</ref> based on the open source CUDA client originally released by puddinpop<ref>[http://www.bitcointalk.org/index.php?topic=133.msg13135#msg13135 puddinpop's open source CUDA miner]</ref>.

Subsequently the java [[DiabloMiner]] based on m0mchil's was created by Diablo-D3<ref>[http://www.bitcointalk.org/index.php?topic=1721.0 Diablo's announcement on the forum]</ref>.

Puddinpop has also released a C++ OpenCL client capable of being compiled into the GUI client or daemon, or as a stand alone RPC miner<ref>[http://www.bitcointalk.org/index.php?topic=2444.0 puddinpop's RPC miners]</ref>.

Another miner was released by Jedi95 & CFSworks released [[Phoenix miner]]<ref>[http://www.bitcointalk.org/index.php?topic=6458.0 Jedi95 & CFSworks phoenix miner]</ref> which can work with memory underclocked to 300MHz and scans whole 232 nonce space.

BitTornado is another OpenCL Miner that supports ATI and NVIDIA Cards. It was released by Chris Evans<ref>[http://mirror.transact.net.au/pub/sourceforge/b/project/bi/bittornado/ BitTornado by Chris Evans]</ref>.

See the [[Mining Hardware Comparison]] page for detailed statistics on the hash rates that can be achieved with various hardware.

==See also==

* [[Mining]]
* [[Mining hardware comparison]]
* [[RPC Miner]]
* [[Getwork]]
* [[Getblocktemplate]]
* [http://www.pcper.com/article.php?aid=745 ATI Stream vs. NVIDIA CUDA - GPGPU computing battle royale]
* [http://www.overclock.net/graphics-cards-general/363095-processing-cores-vs-stream-processing-units.html Processing Cores vs. Stream Processing Units]

==References==

<references />

[[Category:Miners]]

BFGMiner

2026-06-23T10:57:31Z

NotATether: rewrite the page to be up to date

'''BFGMiner''' is free software for Bitcoin and other proof-of-work mining. It is written in C and has supported ASIC, FPGA, GPU, and CPU mining devices, along with pool failover, monitoring, dynamic clocking, fan-speed controls, proxy support, and a remote-control API. The upstream repository describes it as a multi-threaded, multi-blockchain, multi-pool miner.<ref>{{cite web|url=https://github.com/luke-jr/bfgminer|title=BFGMiner source repository|publisher=GitHub|accessdate=23 June 2026}}</ref> It also includes support for OpenWrt-capable routers.

BFGMiner was important during the transition from GPU and FPGA mining to ASIC mining. For current Bitcoin mainnet mining, specialized SHA-256 ASIC hardware dominates. GPU and CPU mining is now mainly historical, educational, testing-oriented, or relevant to non-Bitcoin use cases unless a user has a specific supported purpose.

==Features==

Historically, BFGMiner has included support for ASIC and FPGA mining devices, OpenCL GPU mining workflows, CPU mining support for testing or non-Bitcoin use cases, multiple pools and pool failover, proxy support, local device monitoring and control, overclocking and fan-speed controls for supported hardware, <code>getblocktemplate</code>, APIs for monitoring and management, and OpenWrt-capable routers.

Hardware support has changed over time. Users should verify support for a specific device from the upstream repository, release notes, and current build options before purchasing or configuring mining hardware.

==Device support==

BFGMiner has included a variety of device drivers for Bitcoin SHA256d mining.

===ASIC and FPGA devices===

* [http://www.butterflylabs.com/bitforce-sc-release-notes/ Butterfly Labs's BitForce SC (ASIC) product line]
* [http://launch.avalon-asics.com/ Avalon ASIC mining rig]
* [http://www.butterflylabs.com/product-details/ Butterfly Labs's FPGA BitForce Singles and MiniRigs]
* [http://www.enterpoint.co.uk/cairnsmore/cairnsmore1.html Enterpoint's Cairnsmore1 FPGA mining board]
* [http://fpgamining.com/products/x6500-rev3 FPGA Mining X6500]
* Qi Hardware's [http://en.qi-hardware.com/wiki/Icarus Icarus] and [http://en.qi-hardware.com/wiki/Lancelot Lancelot] FPGA mining boards
* [http://www.btcfpga.com/index.php?route=product/product&product_id=50 BTCFPGA's ModMiner Quad FPGA-based mining device]
* [http://www.ztex.de/ Ztex's FPGA boards]
* [https://bitcointalk.org/?topic=99497 ASICMINER ASICs]
* ''any other device provided for development''

===OpenCL GPUs===

OpenCL GPU support has included devices such as [http://www.amd.com/us/products/Pages/graphics.aspx AMD Radeons].

* Kernels, including BFI_INT patching: Diablo, DiaKGCN, Phatk, and poclbm
* VECTOR support
* Dynamic intensity that keeps the desktop interactive under load and maximises throughput when the desktop is idle
* Integrated overclocking and fan control, including automatic adjustment if configured
* ADL device reordering by PCI bus ID
* GCN (79x0) support

===CPU===

CPU mining support has existed, but was not enabled by default or included in the Windows build described by the older feature list.

==Mining protocols and algorithms==

* Support for the [[Getblocktemplate|getblocktemplate decentralized mining protocol]]
* Scrypt mining support for both CPU and OpenCL GPU mining
* Long poll support, using longpoll from any pool if the primary pool does not support it
* Local generation of more valid work (rollntime) whenever possible, as supported on a per-work-item basis
* Prevention of stale work submission on new block; <code>submitold</code> is also supported
* X-Reject-Reason support

Bitcoin Core's current mining RPC documentation includes <code>getblocktemplate</code>, <code>getmininginfo</code>, <code>getnetworkhashps</code>, <code>submitblock</code>, and related RPCs.<ref>{{cite web|url=https://bitcoincore.org/en/doc/31.0.0/rpc/mining/getblocktemplate/|title=getblocktemplate (31.0.0 RPC)|publisher=Bitcoin Core|accessdate=23 June 2026}}</ref><ref>{{cite web|url=https://bitcoincore.org/en/doc/31.0.0/rpc/mining/getmininginfo/|title=getmininginfo (31.0.0 RPC)|publisher=Bitcoin Core|accessdate=23 June 2026}}</ref>

==Pool and network behavior==

* Automatically detects failing pools and disables them
* Supports multiple pools with multiple intelligent failover mechanisms
* Trickling of extra work to backup pools if the primary pool is responding but slow
* Caching of submissions during transient network outages
* Preemptive fetching of work prior to completion of current work
* Self-detection of new blocks with a mini-database for slow or failing longpoll scenarios, maximum work efficiency, and minimum rejects
* Reuses persistent connections when possible
* Ability to cope with slow routers

==Monitoring and control==

* Multi-device support, including all-device or discrete-device selection
* Summarised and discrete device statistics for requests, accepts, rejects, hardware errors, efficiency, and utility
* Watchdog thread to restart idle threads without crashing the machine if they do not respond
* Summary displayed when quitting
* On-the-fly menu-based management of most settings
* On-the-fly enabling, disabling, and restarting of devices
* Device temperature monitoring for devices that support it
* RPC +/- JSON interface for remote control

==Performance and platform details==

* Very low overhead free C code for Linux and Windows with very low CPU usage
* Heavily threaded code that hands work retrieval and work submission to separate threads so device work is not hindered
* epoll support for interrupting FPGA waiting when new work is available without timeout-looping
* Support for OpenWrt-capable routers

==Installation and security==

Mining software has direct access to hardware and pool credentials, and may run for long periods on networked machines. Download BFGMiner only from trusted upstream sources, review release signatures or hashes where available, and avoid running unverified binaries on machines that hold wallet private keys or exchange credentials.

==See also==

* [[Mining]]
* [[OpenCL miner]]
* [[Getblocktemplate]]
* [[Pooled mining]]
* [[Why a GPU mines faster than a CPU]]

==External links==

* [https://github.com/luke-jr/bfgminer BFGMiner source repository and project page on GitHub]
* [http://luke.dashjr.org/programs/bitcoin/files/bfgminer/ Binaries and Source - All Versions]
* [https://bitcointalk.org/?topic=78192 BitcoinTalk forum thread]
* [http://fabulouspanda.co.uk/commandline/bfgminer/ bfgminer compiled for Mac OS X]
* [http://www.bitcoinmining.com/bitcoin-mining-software/ Bitcoin Mining Software]

==References==

<references />

[[Category:Miners]]
[[Category:Free Software]]
[[Category:License/GPL-3]]
[[Category:Open Source]]

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]]
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[[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]]