Still Probably Not Wright ⇥ dankaminsky.com

Another year begets another media blitz purportedly revealing the identity of Bitcoin’s pseudonymous creator Satoshi Nakamoto. But there’s a surprising twist this time: it’s the same guy as last time. The other weird thing? Instead of reporters chasing the creator down or someone hacking into his email account, Craig Wright — Nakamoto, allegedly — himself is doing the unmasking. And that’s raised a few eyebrows amongst those, as they say, familiar with the matter.

Wright’s “proof”, as demonstrated to the BBC and Economist, is that he cryptographically signed a Sartre passage with a private key known to belong to Nakamoto. However, as Dan Kaminsky explains, this proof isn’t proof at all:

Wright is pretending he has Satoshi’s signature on Sartre’s writing. That would mean he has the private key, and is likely to be Satoshi. What he actually has is Satoshi’s signature on parts of the public Blockchain, which of course means he doesn’t need the private key and he doesn’t need to be Satoshi. He just needs to make you think Satoshi signed something else besides the Blockchain — like Sartre. He doesn’t publish Sartre. He publishes 14% of one document. He then shows you a hash that’s supposed to summarize the entire document. This is a lie. It’s a hash extracted from the Blockchain itself.

Robert Graham of Errata Security summarizes it in a way that’s a little more digestible:

Craig Wright magically appears to have proven he knows Satoshi’s private-key, when in fact he’s copied the inputs/outputs and made us think we calculcated them.

There’s more, too. Adam Goucher found several problems with the code and mathematical explanation that Wright posted, many of which would have been obvious to undergraduates in a cryptography or security-related field. And then there’s the lingering question of why Wright — if he is Nakamoto — chose such a byzantine method of proving his identity. He could have just spent a coin from Nakamoto’s wallet instead while the press watched.

For his part, Wright says that’s what he’s going to do to. But I’m doubtful. This feels less like a way to reveal the identity of Nakamoto and more like a misguided but so-far successful marketing strategy for Wright’s own interests.

Or, who knows — perhaps aliens invented Bitcoin.