Satoshi Nakamoto (fl. 31 October 2008 – 26 April 2011) is the name used by the presumed pseudonymous person or persons who developed bitcoin, authored the bitcoin white paper, and created and deployed bitcoin's original reference implementation. As part of the implementation, Nakamoto also devised the first blockchain database. Nakamoto was active in the development of bitcoin until December 2010.

There has been widespread speculation about Nakamoto's true identity, with various people posited as the person or persons behind the name. Though Nakamoto's name is Japanese, and inscribed as a man living in Japan, most of the speculation has involved software and cryptography experts in the United States or Europe.

Development of bitcoin

Nakamoto said that the work of writing bitcoin's code began in the second quarter of 2007. On 18 August 2008, he or a colleague registered the domain name bitcoin.org, and created a web site at that address. On 31 October, Nakamoto published a white paper on the cryptography mailing list at metzdowd.com describing a digital cryptocurrency, titled "Bitcoin: A Peer-to-Peer Electronic Cash System".

On 9 January 2009, Nakamoto released version 0.1 of the bitcoin software on SourceForge and launched the network by defining the genesis block of bitcoin (block number 0), which had a reward of 50 bitcoins. Embedded in the coinbase transaction of this block is the text: "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks", citing a headline in the UK newspaper The Times published on that date.

Bitcoin (abbreviation: BTC; sign: ₿) is the first decentralized cryptocurrency. Based on a free-market ideology, bitcoin was invented in 2008 when an unknown entity published a white paper under the pseudonym of Satoshi Nakamoto. Use of bitcoin as a currency began in 2009, with the release of its open-source implementation.^{: ch. 1} In 2021, El Salvador adopted it as legal tender. It is mostly seen as an investment and has been described by some scholars as an economic bubble. As bitcoin is pseudonymous, its use by criminals has attracted the attention of regulators, leading to its ban by several countries as of 2021.

Bitcoin works through the collaboration of computers, each of which acts as a node in the peer-to-peer bitcoin network. Each node maintains an independent copy of a public distributed ledger of transactions, called a blockchain, without central oversight. Transactions are validated through the use of cryptography, preventing one person from spending another person's bitcoin, as long as the owner of the bitcoin keeps certain sensitive data secret.