Bitcoin: Difference between revisions
Polargeo 3 (talk | contribs) →External links: Removing links to forum and chat. Talkpage discussion does not demonstrate these are acceptable per WP:EL |
Undid revision 402989916 by Polargeo 3 - Quit owning the article and work to some sort of consensus. The talk page covered this issue |
||
| Line 113: | Line 113: | ||
==External links== |
==External links== |
||
* {{Official website|http://www.bitcoin.org/}} |
* {{Official website|http://www.bitcoin.org/}} |
||
* [http://www.bitcoin.org/smf/ Bitcoin forum] |
|||
* [irc://irc.freenode.net/bitcoin #bitcoin-dev] on freenode |
|||
[[Category:Electronic currencies]] |
[[Category:Electronic currencies]] |
||
Revision as of 21:05, 18 December 2010
 | |
| Developer(s) | Satoshi Nakamoto |
|---|---|
| Initial release | February 4, 2009 |
| Stable release | 0.3.19
/ December 13, 2010 |
| Written in | C++ |
| Operating system | Windows, Linux, Mac OS X |
| Size | 5.2 MiB - 9.7 MiB |
| Type | Electronic money |
| License | MIT License |
| Website | www |
Bitcoin is a digital currency created in 2009 by Satoshi Nakamoto. It is also the name of the open source software designed in order to use this currency. It is one of the first implementations of a concept called cryptocurrency, which was first described in 1998 by Wei Dai on the cypherpunks mailing list.
The main properties of bitcoin are a full decentralisation via a peer-to-peer network, and the use of cryptographic functions in order to establish confidence in the currency. Unlike most other currencies, bitcoin does not rely on any trusted central issuer.
Basis
 |
Bitcoin is a peer-to-peer network where all the nodes share a database of token values called bitcoins. Each record in this database assigns a quantity of bitcoins to its owner's address, which in a mathematical sense, is a hash value of a public key whose corresponding private key is known only to the owner. Addresses in human-readable form are strings of random numbers and letters around 33 characters in length, of the form 1rYK1YzEGa59eN9Aa7w7KUF2Za4jAYYTd. Any person using Bitcoin can own multiple addresses, and in fact can generate new ones without any limit, as generating a new address is simply equivalent to generating a public/private key pair. Generating new addresses is relatively instantaneous and requires no contact with any nodes of the network. Creating single-purpose/single-use addresses will help to preserve anonymity.
A transfer of bitcoins between owners occurs when the original owner (i.e. the sender) broadcasts a digitally signed message relinquishing ownership of the coins and transferring them to a new owner. The rest of the network confirms the validity of the transfer by confirming that the hash value of the sender's public key equals the address recorded by the distributed database, and further, that the digital signature was signed using the corresponding private key. Knowledge of the private key is required in order to transfer the corresponding amount stored in the network. Therefore, ownership of bitcoins is equivalent to possession of the private cryptographic keys.
Bitcoin uses cryptographic principles to prevent double spending. To do so, the network elects a specific node on regular time intervals. This node then has the task of validating current known transactions. Election process involves the execution of a CPU consuming task, based on the proof of work concept created by David Chaum. Each elected node is granted a certain amount of bitcoins, as a reward for its participation in the network. This is the only way bitcoins are created in the system.
The system allows for a maximum of 21 million bitcoins. Any attempt to change the source code to modify this amount would result in rejection by other nodes of any transaction emitted by such a modified program.
Economics
| ISO 4217 | |
|---|---|
| Demographics | |
| User(s) | Supranational, Internet-based |
| Issuance | |
| Central bank | None; decentralized, distributed |
| Valuation | |
| Inflation | Approximately predetermined[1] |
The Bitcoin economy as of December 2010 is largely experimental and consists chiefly of early adopters. Bitcoin is accepted for both online services and tangible goods.[2][3][unreliable source?] The Electronic Frontier Foundation, accepts bitcoin donations.[4] Traders exchange regular currency (including US dollars, Russian rubles, and Japanese yen) for bitcoins through exchange sites.[5][self-published source?][6]
Monetary differences
As opposed to conventional fiat currency, the bitcoin differs in that no overseer can control the currency due to its decentralised nature,[7] mitigating possible instability caused by central banks. There is a limited controlled inflation hardcoded in the Bitcoin software, but it is predictable and known to all parties in advance.[1][self-published source?] Inflation cannot therefore be centrally manipulated to effect redistribution of value from general users. The predetermined growth of bitcoins protects the system against wild supply swings due to externalities as can happen with traditional commodity currencies.[citation needed]
Transfers are facilitated directly without the use of a financial processor between nodes. This type of transaction makes chargebacks impossible. The Bitcoin client broadcasts the transaction to surrounding nodes who propagate the payment across the network. Corrupted or invalid transactions are rejected by honest clients. Transactions are mostly free, however a fee may be paid to other nodes to prioritize transaction processing.[1][self-published source?]
The total supply of bitcoins tends to 21 million BTC over time. The money supply grows as a geometric series every 4 years; by 2013 half of the total supply will have been generated, and by 2017, 3/4 will have been generated. As it approaches that mark the currency will begin to deflate due to the lack of new introduced currency. However as bitcoins are divisible to eight decimal places, there are no practical limitations to downward price adjustments in a deflationary environment.[8] Rather than relying on the incentive of newly created bitcoins to package transactions, nodes in this period should depend more on their ability to competitively collect transaction fees to process transactions.[1][self-published source?]
Technical
Bitcoin is an implementation of Wei Dai's b-money proposal on Cypherpunks in 1998 and Nick Szabo's Bitgold proposal.[1] The principles of the system are described in the Bitcoin White Paper.[1]
Each user on the network has a wallet containing a number of cryptographic keypairs: a public key that is called an address used to receive payments and a private key, stored only on the user's computer to authorize payments from the user. Addresses contain no information about their owner and are generally anonymous.[8] Somebody holding the private key can transfer the bitcoins to another public key by signing a transaction with the bitcoin's earlier public key and broadcasting the interaction to the network as an authorized transaction and requests that the transaction be placed into the block chain. This way, the block chain contains the cryptographic ownership history of each block of coins from the creator of the coin to its current owner.[citation needed]
To prevent users from double-spending their coins (signing the same coin for many recipients), transactions are timestamped by the network with a proof-of-work system. Some of the nodes on the network, called miners by the bitcoin community, collect and record new transactions into candidate blocks for inclusion into the main cryptographic block chain. To be recognized as a valid block to be included other nodes require a proof-of-work and validation of the transactions to prevent double spending. An expected SHA-256 hash against the previous block, produces a new hash containing a certain amount of leading zero bits for this expected proof. Validation of a particular block is computationally trivial compared to creating the block in the first place.[citation needed]
The incentive for running the system is that newly created coins are assigned to the node that manages to complete the new block first, analogous to gold and silver mining.[9] Once a node successfully creates a block, it broadcasts the block to the network. Other nodes receive the block, perform a proof-of-work check, and add it to their chain if it is valid. As more transactions occur, blocks are created and added ad infinitum. The longest proof-of-work block chain is acknowledged to be the oldest and most reliable account of the transaction history. This mechanism is highly tamper-resistant.[1][self-published source?] For an attacker to manipulate the record, he must outpace all other nodes to produce the longest proof-of-work. This becomes exponentially more difficult as time passes, because tampered chains would be rejected by nodes attempting to build a valid chain.[citation needed]
Bitcoin is a completely distributed network, and every node is able to enter or leave the network at will. When a node joins the network, it automatically accepts the longest proof-of-work as the most reliable one.[citation needed]
See also
References
- ^ a b c d e f g Nakamoto, Satoshi (24 May 2009). Bitcoin: A Peer-to-Peer Electronic Cash System (PDF). Retrieved 14 December 2010.
{{cite book}}: CS1 maint: date and year (link) - ^ Bitcoin traders list
- ^ Merchants accepting Bitcoin
- ^ EFF Bitcoin donation page
- ^ Bitcoin Charts
- ^ Thomas, Keir (2010-10-10). "Could the Wikileaks Scandal Lead to New Virtual Currency?". PC World. Retrieved 2010-10-10.
- ^ Bitcoin FAQ
- ^ a b Nathan Willis (2010-11-10). "Bitcoin: Virtual money created by CPU cycles". LWN.net.
- ^ Luongo, Thomas (2010-07-23). "The FED's Real Monetary Problem". LewRockwell.com. Retrieved 2010-10-12.
External links
- Official website
- Bitcoin forum
- #bitcoin-dev on freenode