Four months have passed since the world learned the name of Craig Wright, a man who, as WIRED wrote in December, either created Bitcoin or very badly wants someone to believe he did.
Now rumors are swirling through the Bitcoin world that Wright himself is poised to publicly claim—and possibly offer some sort of proof—that he really is Satoshi Nakamoto, the mysterious inventor of Bitcoin. If he does, he’ll have to convince a highly skeptical cryptography community for whom “proof” is a serious word, and one that requires cryptographic levels of certainty.
The suggestion is that Wright, an Australian cryptographer and security professional, has arranged to perform a demonstration for media in London sometime in the next week that’s intended to convince the world he’s bitcoin’s creator. Luckily for any legitimate claimant to the Satoshi throne—and for bitcoiners tired of the long succession of unproven candidates and speculation—there are some clear, almost incontrovertible ways for Satoshi Nakamoto to prove himself. When WIRED asked bitcoiners and cryptographers what it would take to convince them that Craig Wright is that long-lost Bitcoin founding father, they suggested a variety of methods, each with its own level of certainty. But there’s one form of proof that would be considered airtight for all but the most skeptical skeptics: what Johns Hopkins cryptographer Matthew Green describes as “show me the money.”
If Wright created Bitcoin, he should have access to the keys that control the earliest bitcoins mined on his computer or computers. Those coins have never moved in bitcoin’s seven-year history, despite at times being worth as much as a billion dollars based on Bitcoin’s exchange rate. (They’re valued today at closer to $400 million.) And that hoard of cryptographic treasure, held in a series of bitcoin addresses that each contains 50 bitcoins, are controlled by a collection of private keys—secret strings of characters—that in theory only Nakamoto possesses. If Wright can prove possession of the keys by moving some portion of those oldest bitcoins to a different address, Green says he’d be convinced. “It would be unmistakable,” says Green. “You’d see big piles of old money moving around. That’s the cryptographic miracle I want to see.”
That still wouldn’t necessarily be enough proof, however, for Jerry Brito, director of the cryptocurrency research group Coin Center. Brito points out that Nakamoto ought to possess one key that’s associated with Bitcoin’s so-called Genesis Block, the beginning of the public ledger of bitcoin transactions called the Blockchain. As a quirk of Bitcoin’s design, those first Genesis Block bitcoins can’t be moved or spent, but the key associated with them could be used to sign a message. So, Wright’s strongest proof would be to not only sign a message with that key, Brito says, but to sign messages with the keys from dozens of the first bitcoin blocks until no doubt remains. If Wright proved possession of one or two early blocks of bitcoins but not the Genesis Block or a broad collection of unmoved early coins, Brito says he’d still have suspicions; perhaps Wright started mining in secret very early, for instance, which could also explain his control of an early key. “If you only have the key to, say, the sixth block, why is that the only key he has?” Brito says. “If you’re Satoshi you should be able to sign and also moves funds from a lot of the early blocks.”
And there’s yet another key that Wright might use to try to prove his bitcoin claim: a PGP key long believed to be controlled by Nakamoto and attributed to him on the PGP key server run by MIT. While one blog post written by Craig Wright included a PGP public key that, when checked against the MIT server, was associated with the email address [email protected], that’s not the same, older key, which is associated with the slightly different address [email protected] But Brito points out that Nakamoto’s PGP has never actually been publicly used to sign anything, making it hard to definitively prove that it’s actually his. And he adds that, of course, any key could have been stolen from a hacked computer or somehow shared by the real Satoshi Nakamoto with associates.
Gavin Andresen, one of the few people in the world who’s corresponded by email with Satoshi Nakamoto before the bitcoin founder ghosted from the internet in 2011, has his own list of criteria for Wright to prove himself, which he first shared with the Financial Times, and it’s long. He wants messages signed with both Nakamoto’s PGP key and keys from early bitcoin blocks, private messages he sent to Andresen alone, and an emailed correspondence with Wright to get a feel for whether he’s the same person Andresen communicated with in Bitcoin’s early days. “It’d take multiple lines of evidence to convince me,” Andresen wrote in an email to WIRED.
If bitcoiners like Andresen and Brito are setting a high bar for Wright, it’s because serious holes have already been poked in his resumé. Wright first came to WIRED’s attention through a large collection of leaked emails, meeting transcripts and accounting documents, as well as old posts from his blog that seemed to strongly suggest he’d created bitcoin. But WIRED also found that some of those blog posts had been backdated, either as part of a hoax or as a sign that Bitcoin’s creator was ready to take credit for his work. After both WIRED and Gizmodo published our findings on Wright’s background, other inconsistencies appeared, including the fact that two PhDs Wright claimed to have received from Charles Sturt University in Australia don’t appear to exist, nor do a pair of supercomputers Wright claimed to own and even managed to get listed in the Top500 list of the world’s most powerful supercomputers.
“This man has a big credibility gap to overcome,” Brito says. “I’m open to being convinced he’s Satoshi. But there’s a lot of evidence in the not-Satoshi column.”
Brito also points out that the real Satoshi Nakamoto has sought privacy above fame for the last seven years, and that Wright’s anticipated show of proving his Bitcoin creation to media seems out of character for his attention-averse, would-be pseudonym. It’s possible that another reason for Wright’s demonstration is that he’s being extorted by a hacker who has his files, a claim his friend, cryptographer Ian Grigg, has made. In theory, he may now be trying to defang that extortion threat by outing himself.
Proving that he’s the one true creator of Bitcoin may be the least of Wright’s problems. Shortly after WIRED’s and Gizmodo’s initial stories were published, his home near Melbourne was raided by the Australian Federal Police working on behalf of the Australian Tax Authority. Australian officials declined to comment to WIRED at the time, but officials later told an Australian newspaper that they believe Wright “is not the creator of Bitcoin and that he may have created the hoax to distract from his tax issues.”
With all that room for reasonable suspicion, it’s no wonder that skeptics are hesitant to believe that Wright is Bitcoin’s founding father. Even if he does perform the “cryptographic miracle” of moving Satoshi’s oldest bitcoins or signing a message with the Genesis Block key, some doubters will almost certainly argue that Wright somehow stole or hacked the keys from the cryptocurrency’s true inventor. But for those with an open mind, moving a few chunks of the so-called “bitcoin billion” should be proof enough, says Dan Kaminsky, a well-known security researcher with a history of bitcoin analysis. Even the theory that Wright might have somehow hacked Nakamoto’s computer hardly discounts that proof, Kaminsky argues. “Every computer can be hacked. But if he hacked Satoshi, then this guy knew who the real Satoshi was, and that’s more than what the rest of us can say,” Kaminsky points out. “If Wright does a transaction with one of these keys, he’s done something no other wannabe-Satoshi has done, and we should recognize that.”