Candidate iO from Homomorphic Encryption Schemes
We propose a new approach to construct general purpose indistinguishability obfuscation (iO) Our construction is obtained via a new intermediate primitive that we call split fully homomorphic encryption (split FHE) which we show to be sufficient for constructing iO. Specifically, split FHE is FHE where decryption takes the following two step syntactic form: (i) A secret decryption step uses the secret key and produces a hint which is (asymptotically) shorter than the length of the encrypted message, and (ii) a public decryption step that only requires the ciphertext and the previously generated hint (and not the entire secret key) and recovers the encrypted message. In terms of security, the hints for a set of ciphertexts should not allow one to violate semantic security for any other ciphertexts.
IACR Cryptol. ePrint Arch.