Zero-Knowledge Proof to prove hash of plaintext without decrypting

TheStrangeQuark

8/23/24, 8:53 PM

I'm decently new to cryptography and am trying to wrap my head around zero-knowledge proofs and applications. One use case that I am trying to figure out a strategy for is the following:

I have some plaintext that I'm going to encrypt and give to someone. They can't decrypt the ciphertext but want to verify the hash of the plaintext.

This seems like a place where a zero-knowledge proof is applicable but I'm not sure what the actual strategy looks like for implementing it. I can make a hash of the plaintext but how can I prove that that hash corresponds to the ciphertext that I'm giving them?

0 + 2

zero-knowledge-proofs

Geoffroy Couteau

8/24/24, 6:23 AM

Zero-knowledge proofs work perfectly fine here (the hash is part of the statement, it is not revealed as part of the proof). I guess your question is rather how to concretely build the right ZK proof. This strongly depends on your encryption scheme and hash function, so let me ask: do you have constraints on which encryption scheme and which hash function your system uses? The intuition is: the more you can use something algebraic (ElGamal encryption, a Pedersen hash, etc), the easier it will be to get an efficient ZK proof. Otherwise, it's feasible but can be heavier.

TheStrangeQuark

8/24/24, 11:22 AM

@user93353 If it's not a zk proof, then is there something else I should research for achieving this goal?

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Zero-Knowledge Proof to prove hash of plaintext without decrypting

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