0
$\begingroup$

Assuming that there is a sender and multiple receivers, the sender will send the signature $\sigma$ of a certain message $m$ to all receivers, and the signatures $\sigma$ received by these receivers are the same. Besides zero-knowledge proof, what other technology can realize the consistency proof of signatures?

$\endgroup$
1
  • $\begingroup$ Also, what if I want to prove the validity of the signature $\sigma$ on top of the consistency?How can I prove both consistency and signature validity (that is, the signer truly and correctly generated)? $\endgroup$
    – Anja
    Commented Jul 10 at 1:21

1 Answer 1

1
$\begingroup$

The question is a bit vague, but here are two remarks:

  • You could use a signature scheme that has unique signatures. That is, for a message $m$, there exists a unique signature $\sigma$ that correctly verifies. Then, simply by checking their signature on $m$, all receivers are convinced by design that they got the same signature.

  • If for some reason you don't want to use unique signatures, what's wrong with simply asking the receivers to exchange their signatures (via a straightforward echo broadcast) to check that they are the same?

Note that contrary to what you wrote in the original question, I don't see any reason why zero-knowledge would help here. There's no witness to hide (since $\sigma$ is sent to everyone), and no clear statement (you don't want to prove an NP relation, you want to prove that you did something: that you sent a message to someone else. This is unrelated to the type of things ZKP are used to prove).

$\endgroup$
2
  • $\begingroup$ If on this basis, then prove that the signature $\sigma$ is valid. Is to prove that the signature $\sigma$ is valid while proving consistency. How should this be proved? $\endgroup$
    – Anja
    Commented Jul 10 at 1:03
  • $\begingroup$ A signature is publicly verifiable. It does not matter how it was generated: just run the verification algorithm and check if it returns 1. There is no need for a proof of validity, every receiver can check it themself. $\endgroup$ Commented Jul 10 at 12:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.