Deduplication On Cloud Storage Based On Ring-LWE

With the fast increasing of web users,information data are an exponential explosive growth.Mass of the same data are stored in the cloud server with different ciphertexts which are encrypted by different users.This certainly reduces the resource utilization of cloud service.Therefore,under the premise of the full protection of user’s privacy,how to efficiently deduplicate encrypted files has become a very important problem.Most of the current deduplication schemes are based on the convergent encryption.However,in convergent encryption,the encryption key is generated from the input files in a deterministic way and files with low-entropy might be insecure under the brute force attack.Some schemes build a Merkle tree over the encoded file to prove the ownership but are inefficient for the need of high computing ability of users.To make the encryption key independent w:ith the file content,there are some schemes that,choose a third party server to distribute keys.But they are hard to meet the security requirements.Furthermore,most of the schemes are based on the intractability of the integer factorization problem and the discrete logarithm problem.Nevertheless,quantum computers allow more efficient solution for those problems.Thus,the security of the current schemes couldn’t satisfy the request of the users in the future.In our scheme,the user first encrypts his file with Ring-LWE algorithm.Then subsequent users use the zero-knowledge proof based on lattice to prove ownership by their file hash value which keeping the entropy of the files.Only those who have proved their ownership can retrieval the private key of the original user by the hidden credential retrieval.Contrasting with previous schemes,our encryption key is independent with the file,so we can come through the insecurity caused by the low-entropy file in the convergent encryption.By introducing the HCR protocol,our scheme doesn’t appeal to any third party server to transmit the key.Apart from above,our scheme can resist quantum attack for the particular hard problems that we use.