When Craig Wright, an Australian businessman, was singled out last year as being Satoshi Nakamoto, the anonymous creator of bitcoin, the claims were met with widespread skepticism. The evidence at the time was either too circumstantial to be believable, or was likely fabricated.
Now, Wright is back to prove he really is Satoshi, and not much has changed—despite new evidence, Wright still hasn't done the one thing that would definitively prove that he is Satoshi Nakamoto.
A pair of reports in The Economist and the BBC lay out Wright's proof: a cryptographic signature associated with the private key that controls a bitcoin address associated with "block nine"—the ninth block of bitcoin data ever created and uploaded to the public ledger known as the blockchain. According to the reports, Wright demonstrated similar ownership of "block one," the first block of data ever created by users in the bitcoin network.
The cryptographic signature provided by Wright, allegedly from a private key belonging to Satoshi Nakamoto in a long and technically detailed blog post where he claimed to be Satoshi Nakamoto, is here:
While that looks legit, according to experts, the evidence Wright provided seems to actually be worthless. As it turns out, Wright simply reused an old signature from a bitcoin transaction performed in 2009 by Satoshi.
Dan Kaminsky, a well-known security researcher, wrote in a post debunking Wright's alleged evidence that the whole thing is a scam. "Satoshi signed a transaction in 2009. Wright copied that specific signature and tried to pass it off as new," he added on Twitter. "He's lying. Full stop."
Longtime bitcoin developers also pointed out that this signature could have been copied from a public source, and does not prove that Wright controls the associated addresses.
"It would be like if I was trying to prove that I was George Washington and to do that provided a photocopy of the constitution and said, look, I have George Washington's signature," Bitcoin developer Peter Todd said.
Todd added that someone contacted him by email two weeks ago, claiming to be Satoshi, and using the same signature trick as proof. He says he ignored the email.
"It would be like if I was trying to prove that I was George Washington and to do that provided a photocopy of the constitution and said, look, I have George Washington's signature."
Jeff Garzik, one of Bitcoin's original cadre of code developers, agreed that the evidence provided by Wright doesn't do anything to prove that he is Satoshi Nakamoto.
"Right now, the cryptographic 'evidence' presented could have been produced by anyone." Garzik wrote me in an email. "It was an old already-signed message."
Wright's story has some convinced, however—most notably Gavin Andresen, the bitcoin developer widely recognized as having taken up Nakamoto's mantle, and who worked closely with the anonymous inventor. Andresen wrote in a Reddit comment that he verified Wright controls the key associated with block one. Just as importantly, Andresen said that Wright struck him as being the Nakamoto he communicated with in bitcoin's early days.
"During our meeting, I saw the brilliant, opinionated, focused, generous—and privacy-seeking—person that matches the Satoshi I worked with six years ago," Andresen wrote in a blog post. Andresen's access to bitcoin's code base was revoked as a result of his comments.
Still, Wright's blog post confirming he owns the key to block nine is a dense, technically knotty explanation of something that doesn't prove his claims in the first place. Indeed, there is a much easier way to prove one is Satoshi Nakamoto, which will be explained later.
"He's lying. Full stop."
Wright's drawn-out technical writings might actually be a red herring designed to misdirect the public, according to some skeptics.
"I think if he is Satoshi he is going the long way around to prove it," Alan Woodward, a cryptography expert from the computing department at the University of Surrey, told Motherboard.
"It seems calculated to bamboozle non-specialist journalists and slow the efforts of in-the-know technologists working on refuting or debunking it," said Patrick McKenzie, the CEO of Starfighters, who analyzed and found issues with Wright's alleged signature.
"It is virtually dispositive—like, more likely than the sun coming up in the morning tomorrow—that the evidence offered in the blog post does not establish anything about Wright being Satoshi," McKenzie concluded.
So, what could Wright do to prove he is he is Satoshi Nakamoto?
"Wright needs to sign something new, today, to prove he holds the crypto keys," Garzik wrote in an email.
Remember, however, that Wright has already attempted to prove that he controls the keys to addresses associated with blocks nine and one. But he hasn't proved his association with the most important bitcoin block of all: block zero.
Block one is not actually the first block of bitcoin transaction data ever created. It is, however, the first block of data to be processed, or mined, by someone on the bitcoin network. The decision of who gets to mine said block is basically a function of luck and computing power—if Wright was mining bitcoin in the earliest days, even if he isn't Satoshi, he could have legitimately mined blocks nine and one.
But block zero, known as the "genesis block," was 100 percent, unquestionably created by Satoshi Nakamoto. It was the first block ever made, and it wasn't mined publicly. It's actually permanently written into bitcoin's code base. It is unspendable.
"If you're trying to prove it, you should obviously just sign a message with block zero and go from there."
If Wright still has the private keys associated with blocks one and nine—and he is, in fact, Satoshi Nakamoto—then it would stand to reason that he would also have the key associated with the block that started it all.
"If you're trying to prove it, you should obviously just sign a message with block zero and go from there," said Todd.
Wright has said that he's done "jumping through hoops" to prove that he is who he claims to be. But the truth is that the only person making him go through elaborate technical processes to prove his identity is himself.
There's a very simple and easy way for Wright to definitely prove that he is Satoshi Nakamoto, and he could do it right now, if he wanted: sign a message with the key associated with bitcoin's genesis block.