Is there a way to prove that two ElGamal ciphertexts encrypt the same message with different public keys without knowing the private keys?

The prover is the producer of both ciphertexts.

  • 2
    $\begingroup$ Is this homework? Also, are those two ciphertexts encrypted to the same public key? Are you asking whether the holder of the private key(s) can generate a zero-knowledge proof, or whether someone with only the public keys can deduce it? $\endgroup$ – poncho Mar 24 at 12:20
  • $\begingroup$ I edited the question to answer your questions. $\endgroup$ – Fiono Mar 24 at 12:25

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