3 ms·

As far as I understand it (and I'm not a cryptographer!), it is not zero knowledge. Zero knowledge means you can prove you know something without disclosing an

As far as I understand it (and I'm not a cryptographer!), it is not zero knowledge. Zero knowledge means you can prove you know something without disclosing any additional information about it, at all - that's why it's called "zero". And here, a hash of crush name is exposed, so it's not. Check this out for a much better explanation: https://crypto.stackexchange.com/questions/70877/is-a-hash-a-zero-knowledge-proof https://crypto.stackexchange.com/questions/70877/is-a-hash-a...

lvass 4y ago
>Zero knowledge means you can prove you know something without disclosing any additional information, at all This is physically impossible and definitely not what ZK means.
- drdaeman 4y ago
  I could be wrong, yes. But why impossible? Take this example: https://en.wikipedia.org/wiki/Zero-knowledge_proof#Discrete_log_of_a_given_value https://en.wikipedia.org/wiki/Zero-knowledge_proof#Discrete_... - all parties exchange are essentially random numbers (which doesn't count as "additional information"), yet they establish the fact that Peggy knows x. There's that footnote about how r must be truly random, of course, but as long as everything's done right there is no additional information there whatsoever, only random noise. Side note: one thing I certainly don't understand are NI-ZK - while I think I have some rough understanding of how interactive ZK proofs work - well, I mean, I've read Quisquater et al.'s "How to explain zero-knowledge protocols to your children" - but I'm pretty clueless how they manage to make such things non-interactive.
  - lvass 4y ago
    Any information exchange must go through a medium and it's not possible to create one with zero metadata.
    - drdaeman 4y ago
      Oh, I think I see your point now. But I think it's a weird argument, to be honest. I suppose the fact that it's Peggy and Victor who are running that protocol is simply irrelevant. They're talking about that value of x after all, and nothing related to that topic is revealed beyond the proof of the fact that Peggy knows it. If she'd appear in person, wherever she wears a red shirt or a white one would be might be considered "information" but it would be completely out of scope.

lvass 4y ago

>Zero knowledge means you can prove you know something without disclosing any additional information, at all This is physically impossible and definitely not what ZK means.

drdaeman 4y ago
I could be wrong, yes. But why impossible? Take this example: https://en.wikipedia.org/wiki/Zero-knowledge_proof#Discrete_log_of_a_given_value https://en.wikipedia.org/wiki/Zero-knowledge_proof#Discrete_... - all parties exchange are essentially random numbers (which doesn't count as "additional information"), yet they establish the fact that Peggy knows x. There's that footnote about how r must be truly random, of course, but as long as everything's done right there is no additional information there whatsoever, only random noise. Side note: one thing I certainly don't understand are NI-ZK - while I think I have some rough understanding of how interactive ZK proofs work - well, I mean, I've read Quisquater et al.'s "How to explain zero-knowledge protocols to your children" - but I'm pretty clueless how they manage to make such things non-interactive.
- lvass 4y ago
  Any information exchange must go through a medium and it's not possible to create one with zero metadata.
  - drdaeman 4y ago
    Oh, I think I see your point now. But I think it's a weird argument, to be honest. I suppose the fact that it's Peggy and Victor who are running that protocol is simply irrelevant. They're talking about that value of x after all, and nothing related to that topic is revealed beyond the proof of the fact that Peggy knows it. If she'd appear in person, wherever she wears a red shirt or a white one would be might be considered "information" but it would be completely out of scope.