Bitcoin Wiki - User contributions [en]

TradeHill

2011-08-28T18:42:22Z

Juggernaut:

A bitcoin [[currency exchange]] site.

This exchange escrows funds before trading and then matches buyers with sellers. The exchange's web site shows copyright TradeHill Co. Ltd. The FAQ describes how the terms of Use shall be governed by the laws applicable in the Republic of Chile.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
==Adding Funds==
Funds deposited with the exchange for escrow towards placing a buy order include the following.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
===BTC===

* Adding bitcoins to the account balance incurs no fees.

===USD===

* [[Paxum]] ACH or Check
* [[Liberty Reserve]] (instant)
* Bank transfer (Domestic wire)
* International Bank Transfer (International and HSBC) (A fee is incurred, 1-3 business days)
* [[Paxum]]

===AUD===

* Domestic Bank Transfer with any bank in Australia. (Fee)

===CAD===

* [[Paxum]] Bank wire

===CLP===

* CL (Chile) Domestic Bank Transfer (No fees by the exchange, 1-3 business days)

===EUR===

* SEPA transfer (No fee)
* [[Paxum]] Bank wire

===INR===

* IN (India) Domestic Bank Transfer (No fees by the exchange, 3-4 business days)

===PEN===

* PE (Peru) Domestic Bank Transfer (No fees by the exchange, up to 24 hours)

==Withdrawing Funds==

There are no per-day withdrawal limits<ref>[http://twitter.com/#!/TradeHill/status/79231499253198848 We don't have a daily withdraw limit]</ref>.

===BTC===

* There are no fees to withdraw bitcoins from the account.

===USD===

* [[Liberty Reserve]] (Fees 1% up to maximum of $2.95 USD per transaction)
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees to withdraw (ACH) or for use with ATM / Debit card.
* Bank transfer (ACH)
* Bank wire
* Check by mail
* Donation to charity (Red Cross)

===AUD===

* AU (Australia) Domestic bank transfer to any Australian bank. (percentage fee)

===EUR===

* SEPA transfer (No fee within SEPA zone, fee may occur to outside SEPA).
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CAD===

* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CLP===

* Domestic bank transfer to any Chilean bank. (No fee)

===INR===

* Domestic Rupee bank transfer to any bank in India (Fee for deposit may be charged by your bank)

==Trading==

Limit orders are placed with a specific price. When a counterparty is found, the trade will execute. Partial fills are possible.

Market orders are accommodated through a method that involves quotations.

===Fees===

Trades on the exchange incur a commission (fee) from 0.25% to 0.75% of each trade. The actual rate is specified in the user's account profile. A unique aspect of their fee structure incorporates affiliate marketing.
Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
==History==

First mention on the site was on June 8th, 2011<ref>[http://forum.bitcoin.org/index.php?topic=13650.0 Bitcoin Worldwide Exclusive: New Competitor to MtGox: http://TradeHill.com]</ref> which is also the "go live" date display on the exchange's status page<ref>[https://www.tradehill.com/Support/Status TradeHill Updates]</ref>.

On July 25, 2011 the exchange reported anomalies with [[Dwolla]] payments and stopped accepting Dwolla for deposits<ref>[http://tradehillblog.com/2011/07/26/why-we-are-no-longer-accepting-dwolla/ Why We Are No Longer Accepting Dwolla]</ref>.

On August 10, 2011 the exchange resumed providing methods for SEPA transfers for deposit and withdrawal<ref>[http://tradehillblog.com/2011/08/10/tradehill-is-back-on-the-sepa-zone TradeHill is Back on the SEPA Zone!]</ref>.

==See Also==

* [[Buying bitcoins]]
* [[Selling bitcoins]]

==External Links==

* [https://www.tradehill.com TradeHill]
* [http://twitter.com/tradehill @TradeHill] Twitter
* [http://www.youtube.com/watch?v=4sEXmVsiVqM Interview with CEO of Tradehill (Youtube)]

==References==
<References />

[[Category:Exchanges]]
[[Category:EWallets]]

TradeHill

2011-08-28T18:42:11Z

Juggernaut:

A bitcoin [[currency exchange]] site.

This exchange escrows funds before trading and then matches buyers with sellers. The exchange's web site shows copyright TradeHill Co. Ltd. The FAQ describes how the terms of Use shall be governed by the laws applicable in the Republic of Chile.
Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
==Adding Funds==
Funds deposited with the exchange for escrow towards placing a buy order include the following.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
===BTC===

* Adding bitcoins to the account balance incurs no fees.

===USD===

* [[Paxum]] ACH or Check
* [[Liberty Reserve]] (instant)
* Bank transfer (Domestic wire)
* International Bank Transfer (International and HSBC) (A fee is incurred, 1-3 business days)
* [[Paxum]]

===AUD===

* Domestic Bank Transfer with any bank in Australia. (Fee)

===CAD===

* [[Paxum]] Bank wire

===CLP===

* CL (Chile) Domestic Bank Transfer (No fees by the exchange, 1-3 business days)

===EUR===

* SEPA transfer (No fee)
* [[Paxum]] Bank wire

===INR===

* IN (India) Domestic Bank Transfer (No fees by the exchange, 3-4 business days)

===PEN===

* PE (Peru) Domestic Bank Transfer (No fees by the exchange, up to 24 hours)

==Withdrawing Funds==

There are no per-day withdrawal limits<ref>[http://twitter.com/#!/TradeHill/status/79231499253198848 We don't have a daily withdraw limit]</ref>.

===BTC===

* There are no fees to withdraw bitcoins from the account.

===USD===

* [[Liberty Reserve]] (Fees 1% up to maximum of $2.95 USD per transaction)
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees to withdraw (ACH) or for use with ATM / Debit card.
* Bank transfer (ACH)
* Bank wire
* Check by mail
* Donation to charity (Red Cross)

===AUD===

* AU (Australia) Domestic bank transfer to any Australian bank. (percentage fee)

===EUR===

* SEPA transfer (No fee within SEPA zone, fee may occur to outside SEPA).
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CAD===

* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CLP===

* Domestic bank transfer to any Chilean bank. (No fee)

===INR===

* Domestic Rupee bank transfer to any bank in India (Fee for deposit may be charged by your bank)

==Trading==

Limit orders are placed with a specific price. When a counterparty is found, the trade will execute. Partial fills are possible.

Market orders are accommodated through a method that involves quotations.

===Fees===

Trades on the exchange incur a commission (fee) from 0.25% to 0.75% of each trade. The actual rate is specified in the user's account profile. A unique aspect of their fee structure incorporates affiliate marketing.
Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
==History==

First mention on the site was on June 8th, 2011<ref>[http://forum.bitcoin.org/index.php?topic=13650.0 Bitcoin Worldwide Exclusive: New Competitor to MtGox: http://TradeHill.com]</ref> which is also the "go live" date display on the exchange's status page<ref>[https://www.tradehill.com/Support/Status TradeHill Updates]</ref>.

On July 25, 2011 the exchange reported anomalies with [[Dwolla]] payments and stopped accepting Dwolla for deposits<ref>[http://tradehillblog.com/2011/07/26/why-we-are-no-longer-accepting-dwolla/ Why We Are No Longer Accepting Dwolla]</ref>.

On August 10, 2011 the exchange resumed providing methods for SEPA transfers for deposit and withdrawal<ref>[http://tradehillblog.com/2011/08/10/tradehill-is-back-on-the-sepa-zone TradeHill is Back on the SEPA Zone!]</ref>.

==See Also==

* [[Buying bitcoins]]
* [[Selling bitcoins]]

==External Links==

* [https://www.tradehill.com TradeHill]
* [http://twitter.com/tradehill @TradeHill] Twitter
* [http://www.youtube.com/watch?v=4sEXmVsiVqM Interview with CEO of Tradehill (Youtube)]

==References==
<References />

[[Category:Exchanges]]
[[Category:EWallets]]

TradeHill

2011-08-28T18:41:35Z

Juggernaut:

A bitcoin [[currency exchange]] site.

This exchange escrows funds before trading and then matches buyers with sellers. The exchange's web site shows copyright TradeHill Co. Ltd. The FAQ describes how the terms of Use shall be governed by the laws applicable in the Republic of Chile.

==Adding Funds==
Funds deposited with the exchange for escrow towards placing a buy order include the following.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions
===BTC===

* Adding bitcoins to the account balance incurs no fees.

===USD===

* [[Paxum]] ACH or Check
* [[Liberty Reserve]] (instant)
* Bank transfer (Domestic wire)
* International Bank Transfer (International and HSBC) (A fee is incurred, 1-3 business days)
* [[Paxum]]

===AUD===

* Domestic Bank Transfer with any bank in Australia. (Fee)

===CAD===

* [[Paxum]] Bank wire

===CLP===

* CL (Chile) Domestic Bank Transfer (No fees by the exchange, 1-3 business days)

===EUR===

* SEPA transfer (No fee)
* [[Paxum]] Bank wire

===INR===

* IN (India) Domestic Bank Transfer (No fees by the exchange, 3-4 business days)

===PEN===

* PE (Peru) Domestic Bank Transfer (No fees by the exchange, up to 24 hours)

==Withdrawing Funds==

There are no per-day withdrawal limits<ref>[http://twitter.com/#!/TradeHill/status/79231499253198848 We don't have a daily withdraw limit]</ref>.

===BTC===

* There are no fees to withdraw bitcoins from the account.

===USD===

* [[Liberty Reserve]] (Fees 1% up to maximum of $2.95 USD per transaction)
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees to withdraw (ACH) or for use with ATM / Debit card.
* Bank transfer (ACH)
* Bank wire
* Check by mail
* Donation to charity (Red Cross)

===AUD===

* AU (Australia) Domestic bank transfer to any Australian bank. (percentage fee)

===EUR===

* SEPA transfer (No fee within SEPA zone, fee may occur to outside SEPA).
* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CAD===

* [[Paxum]] Free of charge to transfer to Paxum. Paxum charges fees for a bank wire or for use with ATM / Debit card

===CLP===

* Domestic bank transfer to any Chilean bank. (No fee)

===INR===

* Domestic Rupee bank transfer to any bank in India (Fee for deposit may be charged by your bank)

==Trading==

Limit orders are placed with a specific price. When a counterparty is found, the trade will execute. Partial fills are possible.

Market orders are accommodated through a method that involves quotations.

===Fees===

Trades on the exchange incur a commission (fee) from 0.25% to 0.75% of each trade. The actual rate is specified in the user's account profile. A unique aspect of their fee structure incorporates affiliate marketing.

==History==

First mention on the site was on June 8th, 2011<ref>[http://forum.bitcoin.org/index.php?topic=13650.0 Bitcoin Worldwide Exclusive: New Competitor to MtGox: http://TradeHill.com]</ref> which is also the "go live" date display on the exchange's status page<ref>[https://www.tradehill.com/Support/Status TradeHill Updates]</ref>.

On July 25, 2011 the exchange reported anomalies with [[Dwolla]] payments and stopped accepting Dwolla for deposits<ref>[http://tradehillblog.com/2011/07/26/why-we-are-no-longer-accepting-dwolla/ Why We Are No Longer Accepting Dwolla]</ref>.

On August 10, 2011 the exchange resumed providing methods for SEPA transfers for deposit and withdrawal<ref>[http://tradehillblog.com/2011/08/10/tradehill-is-back-on-the-sepa-zone TradeHill is Back on the SEPA Zone!]</ref>.

==See Also==

* [[Buying bitcoins]]
* [[Selling bitcoins]]

==External Links==

* [https://www.tradehill.com TradeHill]
* [http://twitter.com/tradehill @TradeHill] Twitter
* [http://www.youtube.com/watch?v=4sEXmVsiVqM Interview with CEO of Tradehill (Youtube)]

==References==
<References />

[[Category:Exchanges]]
[[Category:EWallets]]

Main Page

2011-08-28T18:41:08Z

Juggernaut:

{| id="mp-topbanner" style="width:100%; background:#f6f6f6; margin-top:1.2em; border:1px solid #ddd;"
| style="width:61%; color:#000;" |

{| style="width:100%; border:none; background:none;"
| style="text-align:center; white-space:nowrap; color:#000;" |
<div style="font-size:162%; border:none; margin:0; padding:.1em; color:#000;">Welcome to the [[Bitcoin]] wiki,</div>
<div style="top:+0.2em; font-size:95%;">For all your bitcoin information needs.</div>
<div id="articlecount" style="width:100%; text-align:center; font-size:85%;">[[Special:Statistics|{{NUMBEROFARTICLES}}]] articles.</div>
'''Improve [[:Category:Stubs|this wiki]] and [[Bitcoin:Contributors Award|earn bitcoins]].'''
|}Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions

| style="width:13%; font-size:120%;" |
* <span class="plainlinks">[http://bitcoin.org Frontpage]</span>
| style="width:13%; font-size:120%;" |
* <span class="plainlinks">[[Forums]]</span>
| style="width:13%; font-size:120%; padding-right: 40px;" |
* <span class="plainlinks">[[IRC channels|Chatrooms]]</span>
|}


{| id="mp-upper" style="width: 100%; margin:6px 0 0 0; background:none; border-spacing: 0px;"
| class="MainPageBG" style="width:55%; border:1px solid #cef2e0; background:#f6e5f1; vertical-align:top; color:#000;" |
{| id="mp-left" style="vertical-align:top; background:#f6e5f1;"
! style="padding:2px;" | <h2 id="mp-tfa-h2" style="margin:3px; background:#e9caef; font-size:120%; font-weight:bold; border:1px solid #a3bfb1; text-align:left; color:#000; padding:0.2em 0.4em;">Bitcoin</h2>
|-
| style="color:#000;" | <div id="mp-tfa" style="padding:2px 5px">{{MainPage_Intro}}</div>
|-
! style="padding:2px" | <h2 id="mp-dyk-h2" style="margin:3px; background:#e9caef; font-size:120%; font-weight:bold; border:1px solid #a3bfb1; text-align:left; color:#000; padding:0.2em 0.4em;">Why</h2>
|-
| style="color:#000;padding:2px 5px 5px" | <div id="mp-dyk">{{MainPage_Reasons}}</div>
|}
| style="border:1px solid transparent;" |

| class="MainPageBG" style="width:45%; border:1px solid #cedff2; background:#f6e5f1; vertical-align:top;"|
{| id="mp-right" style="width:100%; vertical-align:top; background:#f6e5f1;"
! style="padding:2px" | <h2 id="mp-otd-h2" style="margin:3px; background:#efc1e2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">Topic central</h2>
|-
| style="color:#000;padding:2px 5px 5px" | <div id="mp-otd">{{MainPage_Topics}}</div>
|-
! style="padding:2px" | <h2 id="mp-otd-h2" style="margin:3px; background:#efc1e2; font-size:120%; font-weight:bold; border:1px solid #a3b0bf; text-align:left; color:#000; padding:0.2em 0.4em;">FAQ</h2>
|-
| style="color:#000;padding:2px 5px 5px" | <div id="mp-otd">{{MainPage_FAQ}}</div>
|}
|}

== Other pages ==

* '''[[mw:Help:Formatting|Help]]''' - Documentation on wiki editing.
* '''[[Bitcoin.it Wiki|About]]''' - Information on this site.

[[de:Hauptseite]]
[[es:Página Principal]]
[[fr:Accueil]]
[[it:Pagina principale]]
[[pl:Strona główna]]
[[ru:Заглавная страница]]
[[zh-cn:首页]]

__NOTOC____NOEDITSECTION__

BitcoinTalk

2011-08-24T19:39:03Z

Juggernaut:

The Bitcoin Forum is a message board where people interested in the technical details and the development of Bitcoin software can talk to each other. The forum also has places for people who are interested in bitcoin [[:Category:Mining|mining]], in trading with bitcoin, and in the economics of Bitcoin.

The forum is owned by [[Sirius]]. It is administrated by [[:User:Theymos|theymos]], Sirius, and [[:User:Gavinandresen|Gavin]].

==History==

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

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

In July, 2011 the forum was moved to bitcointalk.org in order to make it explicitly unofficial. The "forum" link on the bitcoin.org homepage now simply returns the Google search results for the search terms "bitcoin forums".

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

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

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

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

<p>The Announcements forum is currently moderator access only.</p></blockquote>
Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions

==External links==

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

Pooled mining

2011-08-23T10:45:16Z

Juggernaut:

'''Pooled mining''' is an approach where multiple generating clients contribute to the generation of a block, and then split the block reward according the contributed processing power. Pooled mining effectively reduces the granularity of the block generation reward, spreading it out more smoothly over time.

==Introduction==

With increasing generation difficulty, mining with lower-performance devices can take a very long time before block generation, on average. For example, with a mining speed of 1000 Khps, at a difficulty of 14484 (which was in effect at the end of December, 2010), the average time to generate a block is almost 2 years.

To provide a more smooth incentive to lower-performance miners, several pooled miners, using different approaches, have been created. With a mining pool, a lot of different people contribute to generating a block, and the reward is then split among them according to their processing contribution. This way, instead of waiting for years to generate 50btc in a block, a smaller miner may get a fraction of a bitcoin on a more regular basis.

A '''share''' is awarded by the mining pool to the clients who present a valid [[proof of work]] of the same type as the proof of work that is used for creating [[block|blocks]], but of lesser complexity, so that it requires less time on average to generate.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions.

==Pooled mining approaches==

The problem with pooled mining is that steps must be taken to prevent cheating by the clients and the server. Currently there are several different approaches used.

===The slush approach===

[[Bitcoin Pooled Mining]] (BPM), sometimes referred to as "slush's pool", follows a score-based method. Older shares (from beginning of the round) has lower weight than newer shares, which demotivate cheater from switching between pools inside one round.

===The puddinpop approach===

(As of February, 2011, there are no puddinpop pools running.)

Another approach is the 'metahash' technique, used by puddinpop's [[remote miner]]. Clients generate hashes, and also submit 'metahashes', which are hashes of a large chunk of generated hashes. The server checks that the metahashes are correct (in a round-robin fashion, picking up a metahash from a client that hasn't been checked on the longest), thus preventing clients from simply claiming that they have done work without actually doing the work. The withholding of good blocks by the clients is prevented via the server being in possession of the private key, just as in the previous approach. Rewards are distributed based on the number of metahashes submitted by the clients.

The generated blocks contain multiple keys in the generation transaction, giving fractional bitcoin amounts to each key, in proportion to their hashing contribution for that block.

===The Pay-per-Share approach===

The Pay-per-Share (PPS) approach, first described by [[BitPenny]], is to offer an instant flat payout for each share that is solved. The payout is offered from the pool's existing balance and can therefore be withdrawn immediately, without waiting for a block to be solved or confirmed. The possibility of cheating the miners by the pool operator and by timing attacks is thus completely eliminated.

This method results in the least possible variance for miners while transferring all risk to the pool operator. The resulting possibility of loss for the server is offset by setting the payout lower than the full expected value.

===Luke-Jr's approach ("[[Eligius]]")===
[[User:Luke-Jr|Luke]] came up with a third approach borrowing strengths from the earlier two.
Like slush's approach, miners submit proofs-of-work to earn shares.
Like puddinpop's approach, the pool pays out immediately via block generation.
When distributing block rewards, it is divided equally among all shares since the last valid block.
Unlike any preexisting pool approach, this means that the shares contributed toward orphaned blocks are recycled into the next block's shares.
In order to spare participating miners from transaction fees, rewards are only paid out if a miner has earned at least 1 BTC. If the amount owed is less, it will be added to the earnings of a later block (which may then total over 1 BTC).
If a miner does not submit a share for over a week, the pool sends any balance remaining, regardless of its size.

===The Triplemining approach===
The [[Triplemining]] approach is to bring together a medium-sized pool with no fees and clever redistribution of 1% of every found block to allow your share to grow more rapidly than on any other bitcoin mining pool.

For every found block, Triplemining redistributes 1% of the profits to all minipool owners (people with 1 or more friends mining with them). The redistribution is connected to the shares found by the members of the minipool. So if the hash rate of the minipool members equals or is bigger than yours, the part in the redistribution will be equally bigger.

===P2Pool approach===

[[P2Pool]] mining nodes work on a chain of shares similar to Bitcoin’s blockchain. There is no central point of failure and thus P2Pool becomes DoS resistant.

P2Pool works different from existing mining pool technologies — each node works on a block that includes payouts to the previous shares’ owners and the node itself. 99% of the block reward (the 50BTC reward plus any included transaction fees) is distributed evenly to miners based on work done recently. An additional 0.5% is awarded to the node which solves the block.

===Comparison===

The cooperative mining approach (slush and Luke-Jr) uses a lot less resources on the pool server, since rather than continuously checking metahashes, all that has to be checked is the validity of submitted shares. The number of shares sent can be adjusted by adjusting the artificial difficulty level.

Further, the cooperative mining approach allows the clients to use existing miners without any modification, while the puddinpop approach requires the custom pool miner, which are as of now not as efficient on GPU mining as the existing GPU miners.
[[File:Smallgeneration.png|thumb|Puddinpop miners receive coins directly.]]

Additionally, the puddinpop and Luke-Jr approaches of distributing the earnings by way of including precise sub-cent amounts in the generation transaction for the participants, results in the presence of sub-cent bitcoin amounts in your wallet, which are liable to disappear (as unnecessary fees) later due to a bug in old (before 0.3.21) bitcoin nodes. (E.g., if you have a transaction with 0.052 in your wallet, and you later send .05 to someone, your .002 will disappear.).

Puddinpop and Luke-Jr miners receive coins directly, which eliminates the delay in receiving earnings that is required on slush-based mining servers. However, using some [[eWallet]] services like MyBitcoin for generated coin will cause those coins to be lost.

==See Also==

* [[:Category:Miners|Miners]]
* [[Comparison of mining pools]]
* [[:Category:Pool Operators|Pool Operators]]
* [[Why a GPU mines faster than a CPU]]
* [[Why pooled mining]]
* [[Mining pool reward FAQ]]

==External links==

* [http://21bitcoin.com/pool/ 21bitcoin mining pool, Chinese Interface]
* [http://mining.bitcoin.cz slush's mining pool]
* [http://www.bitcoin.org/smf/index.php?topic=1458.0 puddinpop's mining pool thread]
* [http://blockexplorer.com/block/00000000000233334b157d901714baf59e5b9236227b2878844e52244da4195e example puddinpop block]
* [http://bitclockers.com bitclockers mining pool]
* [http://btcserv.net BTCSERV.net - Bitcoin Mining Pool]
* [http://forum.bitcoin.org/index.php?topic=18313 P2Pool forum]

==References==
<references />

[[Category:Mining]]

Help:Introduction

2011-08-23T03:04:48Z

Juggernaut:

The purpose of this page is to provide a general overview of the Bitcoin system and economy.

==Basic Concepts==

===Currency===

Alice is far away from Bob and wants to buy his [http://www.grasshillalpacas.com/alpacaproductsforbitcoinoffer.html Alpaca socks]. In return, she wants to send him a dollar. A dollar bill is a piece of paper which is very easy to create (by those who can), but which is accepted by people in exchange for valuable products and services in the real world, such as the socks Alice wants to buy. One simple thing Alice can do is put a dollar bill in an envelope, mail it to Bob, and then wait for Bob to send the socks to her.

===Banks===

Another thing Alice can do is to "wire" the money to Bob. She can do that by first giving her dollar bills to an institution called a bank, the job of which is to safe-keep Alice's dollar bills and, in return, to give Alice a written promise (called a "bank statement") that, whenever she wishes, she can come to the bank to take back the same number of dollar bills that she deposited. Since the money is still Alice's, she is entitled to do with it whatever she pleases, and the bank (like most banks), for a small fee, will do Alice the service of "giving" the dollar bills to Bob instead of her. This could be done by sending a person to Bob's door, with Alice's dollar bills in hand (or, better, fresh new dollar bills, if Alice's dollar bills are in bad condition), but usually it is done by Alice's bank by giving the dollar bills to Bob's bank and informing them that the money is for Bob, who will then see the amount in his next statement, or, if he is in a hurry, the next time he contacts his bank asking about how much money they have for him.

Since banks have many customers, and bank employees require money for doing the job of talking to people and signing documents, banks in recent times have been using machines such as ATMs and web servers, that do the job of interacting with customers instead of paid bank employees. The job of these machines is to learn what each customer wants to do with his/her money and, to the extent that it's possible, act on what the customer wants (for example, ATMs can hand cash). In the end, there is very little human involvement in this process, most of the time. The people can always know how much money out of the money that the bank is safe-keeping is theirs, and they are confident that the numbers they see in their bank statements and on their computer screens stand for the number of dollar bills that they can get from the bank at any time they wish. They can be so sure of that, that they can accept those numbers in the same way they accept paper dollars (this is similar to the way people started accepting paper dollars as they accepted gold or silver).

However, the fact that machines are used does not change the structure of this system, which is, as it was, based on a central authority (the bank) which is responsible for keeping records about how much money belongs to whom. Everybody has to rely on this central authority to be honest (i.e. to say the truth about how much money they are safe-keeping in total, or at least to make the paper money available upon demand from the owners). Also, every person has to identify him/herself to this authority, by giving his/her real name, in order to be allowed to get their paper bills back or to send money to another person.

Bitcoin is a system of owning and voluntarily transferring amounts of so-called bitcoins, in a manner similar to an on-line banking interface, but anonymously and without reliance on a central authority to maintain account balances. These bitcoins are valuable because they are useful and because they are limited in supply.

==Bitcoin Basics==

===Creation of coins===
The creation of coins must be limited for the currency to have any value.

New coins are slowly "mined" into existence by following a mutually agreed-upon set of rules. A user "mining" bitcoins is running a program that searches tirelessly for a solution to a very difficult math problem whose difficulty is precisely known. The difficulty is automatically adjusted regularly so that the number of solutions found globally, by everyone, is constant: an average of 6 per hour. When a solution is found, the user may tell everyone of the existence of this new found solution, along with other information, packaged together in what is called a "block".

Blocks contain 50 bitcoins at present. This amount is an incentive for people to perform the computation work required for block generation. Roughly every 4 years, the number of bitcoins that can be "mined" in a block reduces by 50%. Any blocks that are created by a malicious user that do not follow this rule (or any other rules) will be rejected by everyone else. The result is that no more than 21 million bitcoins will ever exist.

Because the "mining" incentive to put fourth the computational power to create blocks will eventually diminish, miners will some day pay for their hardware and electricity costs by collecting [[Transaction_fee|transaction fees]]. The sender of money may voluntarily pay a small transaction fee which will be kept by whoever finds the next block. Paying this fee will encourage the miner to include the transaction in a block more quickly.

===Transferring a coin===
To guarantee that an eavesdropper, Eve, cannot access other people's bitcoins by creating transactions in their names we use a [[Wikipedia:Public-key_cryptography|public key system]] to make digital signatures. In this system, each person, such as Alice and Bob, has a pair of public and private keys which he/she stores in a safe [[Wallet|wallet]]. Only the user with his secret private key can sign a document, such as the transaction to give some of his bitcoins to somebody else, but any one can validate the signature using the user’s public key.

Suppose Alice wants to send a bitcoin to Bob.
* Bob sends his public key to Alice.
* Alice adds Bob’s public key along with the amount she wants to transfer to a message: a 'transaction' message.
* Alice signs the transaction with her secret private key.
* Alice broadcasts the transaction out over the bitcoin network for all to see.

(Only the first step is actually completed by a human. The rest is done by the bitcoin client software.)

As a result, anyone who knows the public keys of both Alice and Bob can now see that Alice agreed to transfer the amount to Bob, because nobody other than Alice has Alice's private key. Alice would be foolish to give her private key to other people, as this would allow them to sign transactions in her name, removing funds from her control.

Later on, when Bob wishes to transfer the same bitcoin to Charley, he will do the same thing:
* Charlie sends Bob his public key.
* Bob adds Charlie's public key along with the amount he wants to transfer to a message: a 'transaction' message.
* Bob signs the transaction with his private key.
* Bob broadcasts the transaction out over the bitcoin network for all to see.

Only Bob can do this because only Bob has the private key that corresponds to the public key Alice included in the previous transaction.

Eve cannot change who the coins belong to by replacing Bob’s public key with her public key, because Alice signed the transfer to Bob using her private key, declaring that the coins which belonged to her now belong to Bob, and Alice's private key is kept secret from Eve. So if Charley accepts that the original coin was in the hands of Alice he will also accept the fact that this coin was later passed to Bob and now Bob is passing this same coin to him.

===Preventing double-spending===
The process described above does not prevent Alice from using a coin in more than one transaction. The following process does. This is the primary innovation behind Bitcoin.

* Details about the [[Transactions|transaction]] are [[Network|sent and forwarded]] to all or as many other computers as possible.
* A constantly growing chain of [[Blocks|blocks]] that contains a record of all transactions is collectively maintained by all computers (each has a full copy).
* To be accepted in the chain, transaction blocks must be valid and must include [[proof of work]] (one block generated by the network every 10 minutes).
* Blocks are chained in a way so that, if any one is modified, all following blocks will have to be recomputed.
* When multiple valid continuations to this chain appear, only the longest such branch is accepted and it is then extended further.

When Bob sees that his transaction has been included in a block, which has been made part of the single longest and fastest-growing block chain (extended with significant computational effort), he can be confident that the transaction by Alice has been accepted by the computers in the network and is permanently recorded, preventing Alice from creating a second transaction with the same coin. In order for Alice to thwart this system and double-spend her coins, she would need to muster more computing power than all other bitcoin users combined.

===Anonymity===
There are no bitcoin "accounts" to set up, no e-mail addresses and no user-names and passwords to give, just for owning bitcoins. Each balance is simply associated with a randomly generated public-private key pair and the money "belongs" to whoever has the private key and can sign transactions with it. Moreover, those keys do not have to be registered anywhere in advance, as they are only actually used if and when there is a transaction involving them. Transacting parties do not need to know each other's identity in the same way that a store owner does not know Bob's name is Bob when Bob goes and buys groceries with cash.

A [[Address|Bitcoin address]] mathematically corresponds to a public key and looks like this:

:15VjRaDX9zpbA8LVnbrCAFzrVzN7ixHNsC

Each person can have many such addresses, each with its own balance, which makes it very difficult to know which person owns what amount. In order to protect his [[Anonymity|privacy]], Bob can even generate a new public-private key pair for each individual transaction. The Bitcoin software encourages this behavior by default. Continuing the example from above, when Charlie receives the bitcoin from Bob, Charlie will not be able to identify who owned the coin before Bob (not without asking Bob).

You have completed reading our Bitcoin introduction!

==Where to see and explore==
You can directly explore the system in action by visiting the [http://blockexplorer.com/ Bitcoin Block Explorer].
The site shows you the latest blocks in the block chain. The [[Block_chain|block chain]] contains the agreed history of all transactions that took place in the system.
Note how many blocks were generated in the last hour which on average will be 6. Also notice the number of transactions and the total amount transferred in the last hour (last time I checked it was about 64 and 15K).
This should give you an indication of how active the system is.

Next, drill into one of these blocks.
Start by noticing that the block's [[hash|hash]] begins with a run of zeros. This what made making it so difficult; a hash that begins with many zeros is much more difficult to find than a hash with few or no zeros. The computer that generated this block had to try many ''Nonce'' values (also listed on the block's page) until it found one that generated this run of zeros.
Next notice the line titled ''Previous block'', each block contains the hash of the block that came before it, this is what forms the chain of blocks.
Now notice all the transactions the block contains. The first transaction is the income earned by the computer that generated this block. It includes a fixed amount of coins created out of thin air and possibly fee collected from other transactions in the same block.

Drill into any of the transactions and you will see how it is made from one or more amounts coming in and out.
The fact that there can be more than one incoming and outgoing amounts, allow the system to join and break amounts in any possible way allowing for any fractional amount needed. Each incoming amount is a transaction from the past (which you can also drill to) coming from an address of someone and each outgoing amount is addressed to someone and will be part of a future transaction (which you can also drill too if it also had already taken place.)

Finally you can drill into any of the [[Address|addresses]] and see what public information is available.

To get an impression of the amount of activity on the Bitcoin network, you might like to visit the monitoring websites [[Bitcoin Watch]] and [[Bitcoin Monitor]]. The first has general statistics on the amount and size of transactions, while the latter shows a real-time visualization of events on the Bitcoin network.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions.

==See Also==

* [http://www.youtube.com/watch?v=Um63OQz3bjo What is Bitcoin?] video introduction
* Installing Bitcoin [[getting started]]
* [[How bitcoin works]]
* [[Using Bitcoin]]
* A gentle introduction to Bitcoin - [[BitcoinMe]]
* Another introduction, ''The Rebooting Of Money'' podcast is found at [[Bitcoin Money]]

[[zh-cn:简介]]

[[de:Einführung]]

Bitcoin

2011-08-23T03:03:14Z

Juggernaut:

[[Bitcoin]] is a decentralized [[Digital currency|cryptocurrency]] invented by programmer [[Satoshi Nakamoto]], who also developed the [[Original Bitcoin client]]. It allows for anonymous and secure ownership and transfers of amounts of bitcoins, without relying on any central server to process the transactions or store the accounts.

Bitcoin is currently accepted in exchange for other currencies, such as dollars and euros, as well as directly for services and tangible goods.

==History==
:Main article: [[History of Bitcoin]]

The first mention of the concept of cryptocurrency is said to have been made in 1998 by Wei Dai on the cypherpunks mailing list, and Bitcoin can trace its origin to the [[B-money Proposal]]. Related to this is the more recent [[Bit Gold proposal]] by Nick Szabo.

The paper [http://bitcoin.org/bitcoin.pdf Bitcoin: A Peer-to-Peer Electronic Cash System] describes the early concepts behind Bitcoin<ref>[http://www.mail-archive.com/cryptography@metzdowd.com/msg09959.html Bitcoin P2P e-cash paper]</ref> and and precedes the first release of Bitcoin software.

The Bitcoin project was registered on November 9th, 2008. The Bitcoin network started up on January 3rd, 2009 with the [[genesis block]]. The genesis block contains a media reference to the dealings of a central banker in the UK.

On February 9, 2011, and for a few days afterwards, Bitcoin sold for over $1 in most exchanges.

Sign up for Tradehill and use this reference code TH-R110998 and receive 10% off all transactions.

==Security==

:Main article: [[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 [http://en.wikipedia.org/wiki/Public-key_cryptography public key cryptography] and thus may be vulnerable to [http://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.

==See Also==
* [[Introduction]]
* [[Getting started]]
* [[Using_Bitcoin|Detailed tutorial]]
* [[How bitcoin works]]
* [[FAQ]]

==References==
<references />

[[Category:Digital currencies]]

[[pl:Bitcoin]]

Bitcoin

2011-08-23T03:01:04Z

Juggernaut:

[[Bitcoin]] is a decentralized [[Digital currency|cryptocurrency]] invented by programmer [[Satoshi Nakamoto]], who also developed the [[Original Bitcoin client]]. It allows for anonymous and secure ownership and transfers of amounts of bitcoins, without relying on any central server to process the transactions or store the accounts.

Bitcoin is currently accepted in exchange for other currencies, such as dollars and euros, as well as directly for services and tangible goods.

==History==
:Main article: [[History of Bitcoin]]

The first mention of the concept of cryptocurrency is said to have been made in 1998 by Wei Dai on the cypherpunks mailing list, and Bitcoin can trace its origin to the [[B-money Proposal]]. Related to this is the more recent [[Bit Gold proposal]] by Nick Szabo.

The paper [http://bitcoin.org/bitcoin.pdf Bitcoin: A Peer-to-Peer Electronic Cash System] describes the early concepts behind Bitcoin<ref>[http://www.mail-archive.com/cryptography@metzdowd.com/msg09959.html Bitcoin P2P e-cash paper]</ref> and and precedes the first release of Bitcoin software.

The Bitcoin project was registered on November 9th, 2008. The Bitcoin network started up on January 3rd, 2009 with the [[genesis block]]. The genesis block contains a media reference to the dealings of a central banker in the UK.

On February 9, 2011, and for a few days afterwards, Bitcoin sold for over $1 in most exchanges.

==Security==

:Main article: [[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 [http://en.wikipedia.org/wiki/Public-key_cryptography public key cryptography] and thus may be vulnerable to [http://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.

==See Also==
* [[Introduction]]
* [[Getting started]]
* [[Using_Bitcoin|Detailed tutorial]]
* [[How bitcoin works]]
* [[FAQ]]

==References==
<references />

[[Category:Digital currencies]]

[[pl:Bitcoin]]
Sign up for tradehill and use this reference code TH-R110998