zlacker

I am not confident enough in this area to to report a vunrability, the networking alone probably makes timing impractical. I thought it was now practical to generate known prefix Sha256, so some information could be extracted? Not enough to compromise but the function is right there.

>>ZiiS+(OP)
Learning a prefix of the hash doesn't really get you anywhere. The hash itself isn't a secret -- it could be published publicly without breaking the security model. You still need to derive a token that hashes to that value in full, and if you can do that then you've broken the hash algorithm by definition.

>>kenton+t2
Yes I guess if you trust the hash implementation completly; I just favour a bit more defence in depth.

>>kenton+t2
Say I got a memory dump from the client system. I don't know what is what but the secret is in their somewhere.

Filtering it down by the hash prefix locally is much leas likly to be detected then spamming the servers.