Bitcoin was first birthed unto the internet by a mysterious programmer who went by the fake name Satoshi Nakamoto. Over the years, quite a few people have been fingered as the man behind the mysterious identity but none definitively, which is kind of amazing given that this person left all kinds of digital traces behind on internet forums and in the digital money itself. It was long assumed that the person behind Bitcoin didn't want to be known and might, after eight years of concealment, never be known.
But now a man has come forward who wants to claim the Nakamoto mantle: Australian programmer Craig Wright, who had previously been fingered by Wired and Gizmodo based on evidence supplied to them by a person who claimed to have hacked Wright. Wright, who prefers to be called "Dr. Craig Wright," officially "came out" to the Economist, the BBC and GQ this week.
The best way for Wright to prove that he is indeed Satoshi Nakamoto would be for him to move some of the $450 million worth of bitcoin known to belong to the Bitcoin creator. That bitcoin was mined by Nakamoto in the currency's early days and has sat untouched since. The person who could move that money would definitively prove that he or she was Nakamoto, or someone who had hacked Nakamoto's computer.
However, Wright didn't do that. He told the Economist that "he can’t send any bitcoin because they are now owned by a trust." Which naturally leads to the question, 'Well, damn son, why didn't you hold onto just a couple?'
So Wright proved his identity a different way. He flew two bitcoin experts to London and did a private demo with them that was the technological equivalent of showing he has the secret credentials to get into Nakamoto's bank account, and thus must be Nakamoto. The experts, notably long-time Bitcoin developer Gavin Andresen, came away from the demo convinced.
That's the most compelling evidence that Wright is Nakamoto but skeptics are understandably annoyed that this demo was conducted privately. The whole driving principle of Bitcoin is that it's a public ledger with visible cryptographic proof that money is where it claims to be. The whole thing works because it's a financial panopticon where everything can be double-checked by anyone using the system. Wright's method to prove he created Bitcoin is fundamentally opposed to the principles that underlie the currency. We have to rely on hearsay rather than direct proof.
As security technologist Rob Graham puts it:
The entire point of Bitcoin is that it's decentralized. We don't need to take Andresen's word for it. We don't need to take anybody's word for it. Nobody needs to fly to London and check it out on a private computer. Instead, you can just send somebody the signature, and they can verify it themselves.
"It's definitely a scam," security researcher Dan Kaminsky told me, after blogging about Wright's simply re-using a signature that was already public. "Well-played, but a scam."
So the sole evidence left is the one-time private demonstration, conducted under circumstances dictated by Wright, with no opportunity for Andresen to double-check the evidence later or show it to anyone else to double check it.
"I'm 99.9% sure the signature process I participated in wasn't faked," Andresen told me by email. "And still 98% sure Craig is inventor of bitcoin."
Andresen may know for almost-sure that Wright is really Nakamoto, but the rest of the Bitcoin community won't believe it unless public proof is provided: That is the nature of Bitcoin and the nature of its followers.