Research Key Technologies Of Proxy Re-encryption From Lattice

A proxy re-encryption(PRE)scheme was proposed by Blaze,Bleumer and Strauss based on Diffie-Hellman key exchange.Proxy re-encryption mainly operates on the ciphertext,and can convert the ciphertext encrypted by the delegator's public key into the ciphertext encrypted by the delegatee's public key.The delegatee uses his private key to decrypt the relevant message without knowing the delegator's private key.Traditional proxy re-encryption schemes can only control their own delegatees.Autonomous path re-encryption can not only control its own delegatees,but also control the whole proxy path.The existing of autonomous path proxy re-encryption can neither resist quantum attacks nor achieve the fine-grained control of encrypted files.In addition,the existing of proxy re-encryption from learning with error scheme cannot achieve fine-grained access and low efficiency.To solve the above problems,this paper proposes two new proxy re-encryption schemes based on autonomous proxy path and ring learning with error problem.The existing autonomous path proxy re-encryption can neither resist quantum attacks nor achieve the fine-grained control of encrypted files.In order to solve this problem,we construct an autonomous path and identity-based conditional proxy re-encryption scheme on lattice,based on the learning with error,autonomous proxy path and condition matching.We design a proxy re-encryption scheme based on the learning with error problem,which can effectively resist quantum attacks.When a higher level delegatee cannot deal with ciphertext,the proxy server automatically converts the ciphertext to the next delegatee,avoiding the ciphertext conversion to the untrusted delegatees.Finally,the scheme can resist the collusion between delegatees and proxy server.To solve LWE-based proxy re-encryption schemes cannot achieve fine-grained access and low efficiency,we construct a ciphertext-policy attribute-based proxy re-encryption scheme based on ring learning with error,using the reconstruction feature of linear secret sharing scheme,ring learning with error hard problems and attribute encryption.In this scheme,we construct public and private keys based on the ring learning with error hard problem,which can shorten the key size and reduce the ciphertext space,thus improving the encryption and decryption efficiency.Moreover,the scheme use the access structure constructed by the linear secret sharing matrix to implement fine-grained control of the delegatees.The user who satisfies the access structure can decrypt through his or her secret key,and the unrelated user cannot obtain the relevant plaintext information.Finally,the scheme can resist collusion.Finally,we proved the security of the two schemes and given the corresponding formal proof.At the same time,we compared the performance of ours scheme with the existing proxy re-encryption.The analysis shows that the scheme is safe and efficient.