Bitcoin Wiki - User contributions [en]

Bitcoind

2011-01-15T18:58:34Z

MrBison:

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[[Image:Bitcoin Original Client.png|thumb|350px|right|The bitcoin original client]]

The '''Original Bitcoin client''' is the first [[bitcoin]] client in the network's history. It is also the official client of the bitcoin project. It's available under the [http://www.opensource.org/licenses/mit-license.php MIT license] for Windows, 32 and 64-bit GNU/Linux-based OSes and Mac OS X.

The client comes in two executables.

== Executables ==

=== Bitcoin (GUI) ===

The bitcoin GUI provides an easy to use wxWidgets-based interface, allowing to receive and send bitcoins, and generate bitcoins using the computer's CPU power.

=== Bitcoind (CLI) ===

The bitcoind CLI interface runs as a daemon, and provides a JSON-RPC interface allowing to control it locally or remotely. [[Original Bitcoin client/API Calls list|Various commands]] are made available by the API.

==External Links==
* [http://sourceforge.net/projects/bitcoin/ Bitcoin Client project on SourceForge]

[[Category:Clients]]

Proof of work

2011-01-15T18:31:28Z

MrBison: /* Example */ shifted the numbers 0,1,2 for better monospaced view, OK?

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A '''proof of work''' is the verifiable result that can only be obtained through a given work. Proofs of work are hard to obtain (i.e. require work), but trivial to check. Proofs of work can be applied to information, you can prove that you did work on a particular number.

One application of this idea is a proposed [http://en.wikipedia.org/wiki/Hashcash method for preventing email spam], requiring a proof of work on the email's contents (including the To address), on every email. Legitimate emails will be able to do the work to generate the proof easily (not much work is required for a single email), but mass spam emailers will have difficulty generating the required proofs (which would require huge computational resources).

This concept is used in bitcoin for block generation. For a block to be valid it must hash to a value less than the current [[target]], this means that each block indicates that work has been done generating it. Each block contains the hash a predecessor block, thus each block has a [[block chain|chain]] of blocks that together contain a large amount of work. Changing a block (which can only be done by making a new block containing the same predecessor) requires regenerating all successors and redoing the work they contain. This protects the block chain from tampering.

== Example ==

Lets say the base string that we are going to do work on is "Hello, World". Our target is to find a variation of it that hashes to a value beginning with '000'. We vary the string by adding a integer value to the end called a [[nonce]] and incrementing it each time. Finding a match for "Hello, World" takes us 98 tries:

Hello world ! 0 : 3f6fc92516327a1cc4d3dca5ab2b27aeedf2d459a77fa06fd3c6b19fb609106a
Hello world ! 1 : b5690c48c2d0a09481186aaa99e4e090901ff2ac4d572e6706dfd30eefc22a27
Hello world ! 2 : 5b6fd9c27fcb54ca23404d9428f081b7c9280ba6370e33a6a20b16f40ce76320
....
Hello world ! 95 : b74f3b2cf1061895f880a99d1d0249a8cedf223d3ed061150548aa6212c88d43
Hello world ! 96 : 447ca2fa886965af084808d22116edde4383cbaa16fd1fbcf3db61421b9990b9
Hello world ! 97 : 000ba61ca46d1d317684925a0ef070e30193ff5fa6124aff76f513d96f49349d

98 hashes on a modern computer is not very much work (most computers can achieve at least 4 million hashes per second). Bitcoin automatically varies the target (and thus the amount of work required to generate a block) to keep a roughly constant rate of block generation. The probability of a single hash succeeding can be found [http://blockexplorer.com/q/probability|here].

In bitcoin things are a bit more complex, especially since the header contains the [http://en.wikipedia.org/wiki/Merkle_tree merkle tree] which depends on the included transactions. This includes the generation transaction, a transaction "out of nowhere" to our own address, which in addition to providing the miner with incentive to do the work, also ensures that every miner hashes a unique data set.

[[Category:Vocabulary]]

[[fr:Preuve de travail]]

Testnet

2011-01-15T18:30:12Z

MrBison: Mostly the edits from the forum topic, but it's better than almost nothing at all.

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The '''testnet''' is an alternative Bitcoin [[block chain]], to be used for testing. This allows application developers or bitcoin testers to experiment, without having to use real bitcoins or worrying about breaking the main bitcoin chain.

==Differences==
* Instead of ports 8333 (listen) and 8332 (JSON-RPC), ports 18333 and 18332 are used.
* Bootstrapping IRC channel is #bitcoinTEST instead of #bitcoin (both on irc.lfnet.org). The built-in node list is disabled.
* A different value of ADDRESSVERSION field ensures no testnet BitCoin addresses will work on the production network.
* The protocol message header bytes are shifted up (0xFABFB5DA instead of 0xF9BEB4D9)

==External links==

* [http://www.bitcoin.org/smf/index.php?topic=363.0 Test Network forum topic]
* [https://github.com/gavinandresen/bitcoin-git BitCoin testnet version at GitHub]
* [https://freebitcoins.appspot.com/test/ Testnet Faucet]
* [http://blockexplorer.com/testnet Testnet Block Explorer]

Bitcoin faucet

2011-01-15T18:13:57Z

MrBison:

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The '''Bitcoin Faucet''' will give bitcoins for free to each visitor. It is operated by [[Gavin Andresen]].

URL: https://freebitcoins.appspot.com/

The bitcoin faucet will give out varying amount of bitcoins per visitor, depending on the amount of bitcoins in the faucet account. Currently, when there are less than 500 bitcoins in the faucet, it gives out 0.05 bitcoins, or 0.50 bitcoins otherwise.

== Testnet ==

The bitcoin faucet will also provide test bitcoins for people who want to do tests on the testnet.

URL: https://freebitcoins.appspot.com/TEST/

[[Category:Services]]

User:MrBison

2011-01-15T18:12:20Z

MrBison: Created page with "Contributors Award participant: 1H6TGijK7T7vn9Gbqs4rMYG6xByrVAE89r Location: Moscow, Russia E-Mail: m.zubrov@gmail.com Jabber: m.zubrov@web-attack.org"

Contributors Award participant: 1H6TGijK7T7vn9Gbqs4rMYG6xByrVAE89r

Location: Moscow, Russia

E-Mail: m.zubrov@gmail.com

Jabber: m.zubrov@web-attack.org