I am pretty new to cryptography.

Recently I run into this question where I have two different public keys with the same private key, and I need them for fully homomorphic encryption.

Let's say messages from party $A$ and party $B$ are encrypted by two different keys and FHE operations are performed on the encrypted messages. Party $C$ has the one private key to decrypt it. The two different public keys are generated using Party $C$'s public key via Key Reencryption.

How do I perform the FHE operations on these two messages encrypted by different public keys?

P.S. I am using the Palisade library to implement my idea. A little suggestion on how to implement this on Palisade would also be really appreciated.

  • $\begingroup$ Update: I found one solution in this survey paper(arxiv.org/pdf/2007.09270.pdf). So in section 5.2, MKHE basically concatenates the keys to have a final key. It seems to meet my goal here but I am still trying to implement this. Not sure if it works or not and there might be a better solution out there. $\endgroup$ – Jimmy Sep 30 '20 at 21:32

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