ON PAPER—or at least on the blockchain—Satoshi Nakamoto is one of the richest people on the planet. Bitcoin is a semi-anonymous currency and Mr Nakamoto is a pseudonymous person, so it is hard to be sure; but he is generally reckoned to own around 1.1m bitcoin, or around 5% of the total number that will ever exist. When bitcoin hit its peak of over $19,000, that made him worth around $20bn.

But Mr Nakamoto, though actively involved with his brainchild in its early history, has been silent since 2011. An army of amateur detectives has been trying to work out who he really is, but there is frustratingly little to go on. While developing bitcoin he claimed to be male, in his late 30s and living in Japan, but even that information is suspect. There are indications that he may have lived in an American time zone, but his English occasionally contains British idioms. Some of his goldbug-like comments about central banks that “debase the currency” and the evils of fractional-reserve banking led early cyber-libertarian bitcoin enthusiasts to claim him as one of their own. One thing is certain: he values his privacy. To register Bitcoin.org he used Tor, an online track-covering tool used by black-marketeers, journalists and political dissidents.

Still, the legions of sleuths have turned up various candidates, ranging from Japanese mathematicians to Irish graduate students. In 2014 Newsweek, a business magazine, fingered Dorian Prentice Satoshi Nakamoto, an American engineer. He emphatically denied the story, and the next day a forum account previously used by Mr Nakamoto posted, for the first time in five years, to say, “I am not Dorian Nakamoto”—though there are doubts about that account, too.

Attention also focused on Hal Finney, an expert in cryptography, an experienced programmer and a dedicated cypherpunk. He was the recipient in the first-ever transaction conducted in bitcoin, with Mr Nakamoto as the sender. He died in 2014. Andy Greenberg, a journalist, who studied private e-mails between Mr Finney and Mr Nakamoto, concluded that he was probably not bitcoin’s creator. And Mr Finney himself always denied that he was Mr Nakamoto.

Conversely, in 2016 Craig Wright, an Australian computer scientist, explicitly claimed that he was the man everyone was looking for. He invited several news organisations, including The Economist, to witness him prove his claim by using cryptographic keys that supposedly belonged to Mr Nakamoto. He did not convince his audience, so he said he would settle the matter by moving a bitcoin from Mr Nakamoto’s stash. He later decided against it when an online story suggested he could face arrest if he confirmed he was bitcoin’s creator, on the ground of “enabling terrorism”. But the story turned out to be a fake.

According to another theory, Mr Nakamoto is actually a group of people. But for now his, or their, identity remains a mystery. Some think his withdrawal was a matter of principle, to underline the point of a decentralised currency. Perhaps he simply wants a quiet life.

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