Score:0

How to prove that paillier encryption is positive (zero-knowledge)?

us flag

Is it possible that the plaintext encrypted in a ciphertext using paillier encryption is positive without using a zero knowledge range proof?

cn flag
Finite rings don't have positive or negative numbers. If you mean a specific representation of elements, it would be helpful if you explain that. But with that in mind, it's quite likely ZK range proofs are exactly what can do that. If there was another way, it would be called "another ZK range pproof".
fgrieu avatar
ng flag
The question is currently unclear. Perhaps it was asked if the private key holder can make a zero knowledge proof that the plaintext corresponding to a Paillier ciphertext is in $(0,N/2)$ ?
Score:0
my flag

Is it possible that the plaintext encrypted in a ciphertext using paillier encryption is positive without using a zero knowledge range proof?

If you are asking whether it is possible to test whether a Paillier-encrypted value is positive without the cooperation of the holder of the private key, well, we hope not.

If it was, then you can use that method to effectively decrypt the ciphertext (by subtracting various constants that you encrypt, and then testing if the result is positive); this would show that Paillier is insecure.

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.