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Comment by rudolf0 | Hacker News Reader

I agree, but look at what Andresen said:

https://www.reddit.com/r/btc/comments/4hfyyo/gavin_can_you_p...

>Craig signed a message that I chose ("Gavin's favorite number is eleven. CSW" if I recall correctly) using the private key from block number 1.

>That signature was copied on to a clean usb stick I brought with me to London, and then validated on a brand-new laptop with a freshly downloaded copy of electrum.

>I was not allowed to keep the message or laptop (fear it would leak before Official Announcement).

It's quite suspect he wouldn't be allowed to keep the message, and that no public message and signature has been produced. But assuming he's not lying, this doesn't really seem like a scenario where he could be easily tricked.

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My best guess is that Gavin has been duped by a sleight of hand (like a magician would use) by Craig.

My best guess, based on what I've read so far, is this:

- Gavin supplied his own text for the message.

- Craig faked running "sha256sum" on this message on his own laptop. The real "sha256sum" program could have been overwritten with a fake program that always output the same "hash". This is the "magic trick": the "hash" is attacker-controlled, and doesn't actually correspond to Gavin's message. Rather, the hash corresponds to an old message on the block chain - see, e.g., https://gist.github.com/ryancdotorg/893815f426f181d838c1b44a...

- Then from there, presto. The signature validates (and can be validated on Gavin's clean laptop) - because it's a real Satoshi signature, from the public blockchain years ago. But what it validates against is a "fake" hash - that Gavin thinks corresponds to his own message, but actually doesn't.

Easy to see how that would be a very, very convincing demonstration, after some social engineering. But all sleight of hand.

This is (I believe) why Craig has all this blurb up on https://dankaminsky.com/2016/05/02/validating-satoshi-or-not... - it's to hide the trick, which is that he doesn't give us the file "Spartre". He supplies only a (presumably faked) screenshot of sha256sum against this file. Making you type in the hash by hand is misdirection, so you don't realise that you don't have the original file.

Thank you. The part I couldn't understand is how Gavin could verify the signature without retaining the message. But your explanation (with the hash) makes perfect sense.

Wright supplied all the inputs. Amazing.

If my hunch is right, I feel quite sorry for Gavin for having being duped. It would have been very convincing. We're not all James Randi!

Definitely plausible. Gavin will have to elaborate more on the exact process to confirm or deny, though.

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