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.

Nakamoto's true identity is unknown. Various people have been posited as the person or group of people behind his name. He used a Japanese name and gave his residence as Japan, but many have speculated that he is actually a British software and cryptography expert who worked on bitcoin in the United Kingdom. If Nakamoto is an individual person, then his bitcoin holdings make him one of the wealthiest people in the world. His wallet, which has been untouched since 2010, holds an estimated 1.1 million bitcoins.

As of 14 July 2025, their price was more than $123,000 each, meaning the contents of Nakamoto's wallet would have been worth nearly $135 billion.

Nakamoto said that the work of writing bitcoin's code began in the second quarter of 2007. On 18 August 2008, he 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. This note has been interpreted as both a timestamp and a derisive comment on the alleged instability caused by fractional-reserve banking.

Nakamoto continued to collaborate with other developers on bitcoin's software, making all modifications to the source code himself until mid-2010. He then gave control of the source code repository and network alert key to Gavin Andresen, and transferred several related domains to various prominent members of the bitcoin community. In 2011, Nakamoto wrote in an email to co-developer Mike Hearn that he had “moved on to other things,” and he was never heard from again.

Nakamoto has never revealed personal information when discussing technical matters. On his P2P Foundation profile as of 2012, he claimed to be a 37-year-old man who lived in Japan, and gave his date of birth as 5 April 1975. Some theorize that the date referenced the signing of Executive Order 6102, which prohibited the ownership of gold coins in the United States, and 1975 as the year it was repealed. Author Dominic Frisby categorized the date as an "obscure but brilliant reference" and as "extremely political".

It is speculated Nakamoto is unlikely to be Japanese due to their native-level use of English. The bitcoin white paper was not initially translated into Japanese. Analysis of the time of his posts indicates activity aligning with a western time zone. Stefan Thomas, a Swiss software engineer and active community member, graphed the timestamps of each of Nakamoto's bitcoin forum posts (more than 500); the chart showed a steep decline to almost none between 5 a.m. and 11 a.m. Greenwich Mean Time (midnight to 6 a.m. Eastern Standard Time). This was between 2 p.m. and 8 p.m.

Japan Standard Time, suggesting an unusual sleep pattern for someone living in Japan. As this pattern held even on Saturdays and Sundays, it suggested that Nakamoto was consistently asleep at this time.

Others have considered that Nakamoto might be a team of people. Dan Kaminsky, a security researcher who read bitcoin's code, said that Nakamoto was either a "team of people" or a "genius"; Laszlo Hanyecz, a developer who had emailed Nakamoto, had the feeling the code was too well-designed for one person; Andresen has said of Nakamoto's code: "He was a brilliant coder, but it was quirky."

Nakamoto's identity is unknown, but speculations have focused on various cryptography and computer science experts, most of whom are of non-Japanese descent. Bitcoiners and cryptographers have suggested various methods by which a person could prove their identity as Nakamoto, such as moving the earliest bitcoins mined or signing a message with the key associated with the first bitcoins. On the other hand, a denial of being Nakamoto is very difficult to confirm.

In 2016, the Financial Times said that Nakamoto might have been a group of people, mentioning Adam Back, Hal Finney, and Nick Szabo as potential members. In 2018, John McAfee publicly suggested that Adam Back was the creator of bitcoin. In 2020, the YouTube channel Barely Sociable claimed that Back, inventor of bitcoin predecessor Hashcash, is Nakamoto; widespread discussion ensued and Back subsequently denied this.

In 2024, the film Money Electric: The Bitcoin Mystery devotes attention to Back as a Satoshi Nakamoto candidate. The film notes that Back is named in the body of the Bitcoin white paper, and that Back and Nakamoto have a similar writing style. It also highlights Back's move to Malta, his edits to Wikipedia's Bitcoin article that restored its Satoshi Nakamoto section and listed other suspects but not himself, and his appearance on the Bitcointalk forum on 17 April 2013, the same day the size of Nakamoto holdings first became public.

The film characterizes Blockstream, the company Back co-founded in 2014, as a possible "corporate Satoshi". In the documentary, Back says "I thought you might think I'm Satoshi. And I don't want that to be on the record, really".

In 2026, investigative journalist John Carreyrou of The New York Times reported on a series of interactions with Adam Back, suggesting he could be Satoshi Nakamoto. Carreyrou cited Back's cryptographic background, his prior work on Hashcash, and stylometric analyses comparing Back's writing to Nakamoto's. He also noted circumstantial factors, including Back's reduced activity on cryptography mailing lists during the period Nakamoto was active and perceived inconsistencies in Back's recollections of early bitcoin discussions.

During an in-person interview at a bitcoin conference in El Salvador, Back denied being Nakamoto multiple times and attributed the evidence to coincidence. Carreyrou interpreted aspects of Back's responses and demeanor, including a disputed conversational remark, as potentially indicative of authorship. Back rejected this interpretation.