Suppose Alice has a verifiable (message, signature) pair from Cedric, who would not cooperate and routinely uses an algo (ecdsa, eddsa, rsa, or insert yours here) to sign messages.

Alice wants to interactively prove to Bob she has that (message, signature) pair with the valid signature, obviously. It doesn't have to be "zero-knowledge" - she might divulge bits and pieces, but it shouldn't be less hard for Bob to recover complete (message, signature) pair than for Alice to forge the signature altogether.

Obviously, Alice and Bob both have Cedric's public key. I look for an interactive procedure and stochastic proof. Preferably with existing implementations.

  • $\begingroup$ what if you split the message in 100 parts with different signature and give little part of the parts $\endgroup$
    – zjmo
    Commented Nov 12, 2022 at 11:40
  • $\begingroup$ and then maybe add a second signed message containing only 10 part equally disdributed with the relative signature + the signature of the whole message $\endgroup$
    – zjmo
    Commented Nov 12, 2022 at 11:58
  • $\begingroup$ @zjmo and then maybe 10 people named Bob talk to each other :-) $\endgroup$
    – wick
    Commented Nov 12, 2022 at 13:11
  • $\begingroup$ just started reding crypto for dummies ;) $\endgroup$
    – zjmo
    Commented Nov 12, 2022 at 13:14


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