An Efficient Proof of Retrievability Scheme for Fully Homomorphic Encrypted Data

Proof of retrievability (POR) is an interactive knowledge proof technique for a storage server to prove the integrity and ownership of clients’ data without downloading them. In this paper we consider efficiency of the POR scheme, when the data stored in cloud is encrypted under fully homomorphic encryption schemes. We presented a POR scheme with new, efficient homomorphic authenticator, which enables constant-size responses and requests fairly little storage and computational power for the clients. The soundness of our scheme is guaranteed by a game-based security proof, under the security model of Juels and Kaliski’s.