Satoshi Nakamoto

Satoshi Nakamoto
Fields	Digital currencies, Computer science, Cryptography
Known for	Inventing bitcoin

Satoshi Nakamoto is the name used by the person or people who designed bitcoin and created its original reference implementation, Bitcoin Core (formerly known as Bitcoin-Qt).

Development of bitcoin

In May 2008, Nakamoto published a paper on The Cryptography Mailing list at metzdowd.com describing the bitcoin digital currency. In January 2009, Nakamoto released the first bitcoin software that launched the network and the first units of the bitcoin cryptocurrency, called bitcoins.

Nakamoto continued to collaborate with other developers on the bitcoin software until mid-2010. Around this time, he handed over control of the source code repository and network alert key to Gavin Andresen, transferred several related domains to various prominent members of the bitcoin community, and stopped his involvement in the project.

The public bitcoin transaction log shows that Nakamoto's known addresses contain roughly one million bitcoins. As of 30 May 2016, this is the equivalent of US$538 million.

Characteristics

On his P2P Foundation profile as of 2012, Nakamoto claimed to be a 37-year-old male who lived in Japan, but some speculated he was unlikely to be Japanese due to his use of perfect English and his bitcoin software not being documented or labelled in Japanese.

Occasional British English spelling and terminology (such as the phrase "bloody hard") in both source code comments and forum postings led to speculation that Nakamoto, or at least one individual in the consortium claiming to be him, was of Commonwealth origin.

Stefan Thomas, a Swiss coder and active community member, graphed the time stamps for each of Nakamoto's bitcoin forum posts (more than 500); the resulting chart showed a steep decline to almost no posts between the hours of 5 a.m. and 11 a.m. Greenwich Mean Time. Because this pattern held true even on Saturdays and Sundays, it suggested that Nakamoto was asleep at this time. If Nakamoto is a single individual with conventional sleeping habits, it suggests he resided in a region using the UTC−05:00 or UTC−06:00 time offset. This includes the parts of North America that fall within the Eastern Time Zone and Central Time Zone, as well as parts of Central America, the Caribbean and South America.

Candidates

Nick Szabo

In December 2013, a blogger named Skye Grey linked Nick Szabo to the bitcoin's whitepaper using a stylometric analysis. Szabo is a decentralized currency enthusiast and published a paper on "bit gold", which is considered a precursor to bitcoin. He is known to have been interested in using pseudonyms in the 1990s. In a May 2011 article, Szabo stated about the bitcoin creator: "Myself, Wei Dai, and Hal Finney were the only people I know of who liked the idea (or in Dai's case his related idea) enough to pursue it to any significant extent until Nakamoto (assuming Nakamoto is not really Finney or Dai)."

Detailed research by financial author Dominic Frisby provides much circumstantial evidence but, as he admits, no proof that Satoshi is Szabo. Speaking on RT's The Keiser Report, he said "I've concluded there is only one person in the whole world that has the sheer breadth but also the specificity of knowledge and it is this chap ...". But Szabo has denied being Satoshi. In a July 2014 email to Frisby, he said: 'Thanks for letting me know. I'm afraid you got it wrong doxing me as Satoshi, but I'm used to it'. Nathaniel Popper wrote in the New York Times that "the most convincing evidence pointed to a reclusive American man of Hungarian descent named Nick Szabo."

Dorian Nakamoto

In a high-profile March 6, 2014, article in the magazine Newsweek, journalist Leah McGrath Goodman identified Dorian Prentice Satoshi Nakamoto, a Japanese American man living in California, whose birth name is Satoshi Nakamoto, as the Nakamoto in question. Besides his name, Goodman pointed to a number of facts that circumstantially suggested he was the bitcoin inventor. Trained as a physicist, Nakamoto worked as a systems engineer on classified defense projects and computer engineer for technology and financial information services companies. Nakamoto was laid off twice in the early 1990s and turned libertarian, according to his daughter, and encouraged her to start her own business and "not be under the government's thumb." In the article's seemingly biggest piece of evidence, Goodman wrote that when she asked him about bitcoin during a brief in-person interview, Nakamoto seemed to confirm his identity as the bitcoin founder by stating: "I am no longer involved in that and I cannot discuss it. It's been turned over to other people. They are in charge of it now. I no longer have any connection." (This quote was later confirmed by deputies at the Los Angeles County Sheriff's Department who were present at the time.)

The article's publication led to a flurry of media interest, including reporters camping out near Dorian Nakamoto's house and briefly chasing him by car when he drove to an interview. However, during the subsequent full-length interview, Dorian Nakamoto denied all connection to bitcoin, saying he had never heard of the currency before, and that he had misinterpreted Goodman's question as being about his previous work for military contractors, much of which was classified. Later that day, the pseudonymous Nakamoto's P2P Foundation account posted its first message in five years, stating: "I am not Dorian Nakamoto."

Hal Finney

Hal Finney (May 4, 1956 – August 28, 2014) was a pre-bitcoin cryptographic pioneer and the first person (other than Satoshi himself) to use the software, file bug reports, and make improvements. He also lived a few blocks from Dorian Nakamoto's family home, according to Forbes journalist Andy Greenberg. Greenberg asked the writing analysis consultancy Juola & Associates to compare a sample of Finney's writing to Satoshi Nakamoto's, and they found that it was the closest resemblance they had yet come across (including the candidates suggested by Newsweek, Fast Company, The New Yorker, Ted Nelson and Skye Grey). Greenberg theorized that Finney may have been a ghostwriter on behalf of Nakamoto, or that he simply used his neighbor Dorian's identity as a "drop" or "patsy whose personal information is used to hide online exploits". However, after meeting Finney, seeing the emails between him and Satoshi, his bitcoin wallet's history including the very first bitcoin transaction (from Satoshi to him, which he forgot to pay back) and hearing his denial, Greenberg concluded Finney was telling the truth. Juola & Associates also found that Satoshi's emails to Finney more closely resemble Satoshi's other writings than Finney's do. Finney's fellow extropian and sometimes co-blogger Robin Hanson assigned a subjective probability of "at least" 15% that "Hal was more involved than he’s said", before further evidence suggested that was not the case.

Craig Steven Wright

On 8 December 2015, Wired wrote that Craig Steven Wright, an Australian former academic, "either invented bitcoin or is a brilliant hoaxer who very badly wants us to believe he did". Craig Wright took down his Twitter account and neither he nor his ex-wife responded to press inquiries. The same day, Gizmodo published a story with evidence obtained by a hacker who supposedly broke into Wright's email accounts, claiming that Satoshi Nakamoto was a joint pseudonym for Craig Steven Wright and computer forensics analyst David Kleiman, who died in 2013. A number of prominent bitcoin promoters remained unconvinced by the reports. Subsequent reports also raised the possibility that the evidence provided was an elaborate hoax, which Wired acknowledged "cast doubt" on their suggestion that Wright was Nakamoto.

On 9 December, only hours after Wired claimed Wright was Nakamoto, Wright's home in Gordon, New South Wales was raided by at least ten police officers. His business premises in Ryde, New South Wales were also searched by police. The Australian Federal Police stated they conducted searches to assist the Australian Taxation Office and that "This matter is unrelated to recent media reporting regarding the digital currency bitcoin." According to a document released by Gizmodo alleged to be a transcript of a meeting between Wright and the ATO, he had been involved in a taxation dispute with them for several years.

On 2 May 2016, Craig Wright posted on his blog publicly claiming to be Satoshi Nakamoto. In articles released on the same day, journalists from the BBC and The Economist stated that they saw Wright signing a message using the private key associated with the first bitcoin transaction. Wright's claim was supported by Jon Matonis (former director of the Bitcoin Foundation) and bitcoin developer Gavin Andresen, both of whom met Wright and witnessed a similar signing demonstration.

However, bitcoin developer Peter Todd said that Wright's blog post, which appeared to contain cryptographic proof, actually contained nothing of the sort. The Bitcoin Core project released a statement on Twitter saying "There is currently no publicly available cryptographic proof that anyone in particular is Bitcoin's creator." Bitcoin developer Jeff Garzik agreed that evidence publicly provided by Wright does not prove anything, and security researcher Dan Kaminsky concluded Wright's claim was "intentional scammery".

On May 4, Wright made another post on his blog promising to publish "a series of pieces that will lay the foundations for this extraordinary claim". But the following day, he deleted all his blog posts and replaced them with a notice entitled "I'm Sorry", which read in part:

I believed that I could put the years of anonymity and hiding behind me. But, as the events of this week unfolded and I prepared to publish the proof of access to the earliest keys, I broke. I do not have the courage. I cannot.

Adam Back

In early 2020, the investigative journalism-oriented YouTube channel Barely Sociable released a three-part documentary on the history of Bitcoin and the mystery of Satoshi's identity. It reached the conclusion that Satoshi Nakamoto is almost certainly Dr. Adam Back, inventor of the hashcash proof-of-work algorithm used to mine Bitcoin, and co-founder and CEO of the Bitcoin development company Blockstream. The documentary describes Back as a candidate who "literally matches every single detail" of Nakamoto. In analyzing the Bitcoin white paper, it notices that Bitcoin was invented by applying hashcash to the digital ledger described in Wei Dai's "B-Money", and highlights a post by Adam Back from 1998 on the Cryptography Mailing List, where he enthusiastically described wanting to combine these two inventions. Bitcoin was programmed using C++, a language that Back is proficient in. Barely Sociable compares Nakamoto and Back's written communication, noting they both use British English, and double-space after a sentence.

Although Nakamoto and Back both claim to have corresponded with one another, no emails between the two have been found yet. Conversely, many other people associated with Bitcoin's development have publicly-accessible emails to, or from, Nakamoto. The documentary also demonstrates that Back had almost no online presence during the years Bitcoin originated, and unveils a message from Satoshi dated August 15, 2015 that opposed the then-recently created Bitcoin XT fork; Back and Blockstream's developers also opposed Bitcoin XT. In response to the documentary, Back denied that he was Nakamoto and described the documentary's contents as factual, but merely coincidental.

Additionally, Charles Hoskinson, creator of Cardano and co-creator of Ethereum, and businessman and software developer John McAfee have suspected that Adam Back is Satoshi Nakamoto. Hoskinson said Back was his first guess for Satoshi's identity, calling him "the Occam's Razor candidate; right time, right age, right skill set...". McAfee said the British English and double spaces after sentences in the Bitcoin white paper gave away his identity.

Other speculation

• In a 2011 article in The New Yorker, Joshua Davis claimed to have narrowed down the identity of Nakamoto to a number of possible individuals, including the Finnish economic sociologist Dr. Vili Lehdonvirta and Irish student Michael Clear, then a graduate student in cryptography at Trinity College Dublin. Clear strongly denied he was Nakamoto, as did Lehdonvirta.
• In October 2011, writing for Fast Company, investigative journalist Adam Penenberg cited circumstantial evidence suggesting Neal King, Vladimir Oksman and Charles Bry could be Nakamoto. They jointly filed a patent application that contained the phrase "computationally impractical to reverse" in 2008, which was also used in the bitcoin white paper by Nakamoto. The domain name bitcoin.org was registered three days after the patent was filed. All three men denied being Nakamoto when contacted by Penenberg.
• In May 2013, Ted Nelson speculated that Nakamoto is really Japanese mathematician Shinichi Mochizuki. Later, an article was published in The Age newspaper that claimed that Mochizuki denied these speculations, but without attributing a source for the denial.
• A 2013 article, in Vice listed Gavin Andresen, Jed McCaleb, or a government agency as possible candidates to be Nakamoto. Dustin D. Trammell, a Texas-based security researcher, was suggested as Nakamoto, but he publicly denied it.
• In 2013, two Israeli mathematicians, Dorit Ron and Adi Shamir, published a paper claiming a link between Nakamoto and Ross William Ulbricht. The two based their suspicion on an analysis of the network of bitcoin transactions, but later retracted their claim.

Some considered Nakamoto might be a team of people; Dan Kaminsky, a security researcher who read the bitcoin code, said that Nakamoto could either be a "team of people" or a "genius"; Laszlo Hanyecz, a former bitcoin core developer who had emailed Nakamoto, had the feeling the code was too well designed for one person.