There’s been a lot of speculation who Satoshi Nakamoto is. What’s for sure is that he/she/they is the inventor of Bitcoin; i.e. the person who published the original Bitcoin paper and created the first block of the Bitcoin blockchain. If Satoshi traded his Bitcoin for cash, he would also be absurdly rich: As of January 19, 2018, Satoshi’s 980,000 bitcoins are worth 11.7 billion US dollars.
We don’t know who Satoshi is, but even the speculations about his identity are well worth reading. Here are the most popular theories:
1. The NSA is Satoshi
Natalya Kasperskaja, the co founder of the Russian security company Kaspersky Lab, claims that Bitcoin is an invention of US intelligence agencies:
Bitcoin is a project of American intelligence agencies, which was designed to provide quick funding for US, British and Canadian intelligence activities in different countries. [The technology] is 'privatized,' just like the Internet, GPS and TOR. In fact, it is dollar 2.0. Its rate is controlled by the owners of exchanges.
Source: Speech “Modern technologies - the basis for information and cyberwars” at ITMO University St. Petersburg.
Kasperskaja’s claim is not new. Every now and then, someone new comes up with “evidence” that Bitcoin was invented by the NSA / the KGB / Mossad / etc, and that Satoshi Nakamoto is a codename for a group of secret service crypto experts.
However, there’s little evidence for this. Most of these stories are probably just conspiracy theories, or, like in Kasperskaja’s case, [Russian] propaganda.
2. Satoshi is Dorian Prentice Satoshi Nakamoto / Hal Finney / Nick Szabo
Various journalists have claimed to have identified Satoshi Nakamoto. In 2014, Newsweek published a piece about Dorian Prentice Satoshi Nakamoto, a 64-year old ex-engineer and developer living in Temple City, CA. They concluded that the language style of Satoshi’s original paper is amazingly fluent for a Japanese individual, and that it’s therefore much more likely that Satoshi is a US citizen. The (at least somewhat) unique style of his Bitcoin source code also suggests that he’s a single individual, and not a group of people.
Andy Greenberg from Forbes later suggested that crypto expert Hal Finney was connected to Satoshi Nakamoto. Finney was involved in Bitcoin from the start, and received the first test transaction on Jan 12, 2009[6]. Curiously, he also lives in Temple City - just 1.6 miles away from Dorian Nakamoto. Some people even claimed that Finney is Satoshi, but at least Greenberg doesn’t think he is.
When Greenberg visited Finney, Finney showed him his Gmail account where he frequently exchanged mails with Satoshi in the early days of Bitcoin. At that time, no one knew that Bitcoin would become such a big thing in the future. To Greenberg (and to me) it seems unlikely that Finney would have created a fake email exchange with his alter ego.
Others suggested that Nick Szabo is Satoshi. In 2005, Szabo published an idea about “Bit Gold” that was very similar to Bitcoin.[7] Several other things hint at Szabo being Satoshi, though all of them are very speculative in nature. If you want to read more, check out Anonymous' answer to “Is Satoshi Nakamoto really Nick Szabo?”.
I personally don’t believe that any of the aforementioned - or similar names from the early days of Bitcoin - are Satoshi; even though I would not completely rule out the possibility. The most common counter-argument against Szabo and Dorian Nakamoto is that their writing style doesn’t match with the style of the original Bitcoin paper. So even if they were involved, they were certainly not the people who put the idea in writing.
3. The NSA knows who Satoshi is
In a widely-cited Medium article, Alexander Muse tells the story how the NSA identified Satoshi Nakamoto. Muse claims to have this information from a Homeland Security source, although he can’t back this up with any facts.
Muse writes that the NSA used stylometry, i.e. the analysis of the writing style, to identify Satoshi. Stylometry had already been used to compare Finney’s, Szabo’s, and Dorian Nakamoto’s writing style with Satoshi (with a negative result). However, Muse states that these efforts only had a small dataset of publicly available posts, whereas the NSA used a front-door access to all Google and Yaho user accounts and their copies of data flows across fiber optic cables as a basis for their analysis. In other words, the NSA is supposed to have matched all Gmail and Yahoo messages with Satoshi’s paper and forum posts.
Why? Muse writes that the NSA wanted to make sure that Satoshi wasn’t an agent of Russia or China.
According to Muse, the NSA eventually got a positive match, and identified Satoshi. Muse doesn’t say what they did with this information.
What made me wonder: If a Forbes journalist could just walk to Finney and see real emails with the original Satoshi, why would the NSA need to undertake such an expensive analysis? After all, they could just have checked out Finney’s Gmail account to identify Satoshi’s original account.
4. Satoshi is a private person / group of private persons and wants to stay hidden
One of the greatest puzzles in Satoshi’s mystery is why he doesn’t cash in his Bitcoin fortune. Many believe that this has to do with his desire to stay private.
Already at the foundation of Bitcoin, Satoshi took great effort to conceal his identity (most likely because he didn’t know if what he was doing was legal). Even if he would cash in just a small portion of his Bitcoin fortune, this might jeopardize his privacy - and the implications of that could be disastrous.
The media would hunt him down to get insights into his life. Secret services all over the world would observe him. And after all, he’d still have access to a billion-dollar Bitcoin wallet (or a well-filled bank account), which would make him a prime target for criminal organisations all over the world. The news that Pavel Lerner, analyst of crypto exchange Exmo Finance, was kidnapped by Ukranian gangsters, certainly didn’t help to change Satoshi’s mind.