Research Of Cloud Data Deduplication Mechanism Based On Certificateless Cryptography

With the popularity of cloud storage services,the amount of data stored by cloud storage server has exploded.In order to reduce the storage pressure of the cloud server,we can delete the duplicate data stored in the cloud,which is cloud data deduplication.Cloud data deduplication removes redundant data and keeps only one copy in the cloud storage server.The data need to be encrypted and stored in the cloud in the form of ciphertext to ensure user privacy and data security.Therefore,how to detect a ciphertext to find the same files is a challenging problem.The traditional cloud data deduplication scheme has the key escrow problem based on identity-based encryption scheme and the certificate management problem based on the public key encryption scheme.Therefore,this thesis introduced certificateless cryptography technology and proposed a cloud data deduplication scheme based on certificateless cryptography(CDD-CLC).It contains the following two aspects:(1)This thesis designed an efficient certificateless proxy re-encryption(ECL-PRE)scheme.First,we defined certificateless proxy re-encryption(CL-PRE)scheme formally.Then we constructed a security model for this scheme and proposed a whole ECL-PRE scheme.After that,we analyzed the correctness of decryption and security of the scheme,and proved its indistinguishability against chosen-ciphertext attacks(IND-CCA).Finally,the advantages of this scheme in performance were proved through comparing its communication and computing consumption with other schemes and further simulating these schemes by using Java pairing-based cryptography library(JPBC).(2)This thesis designed a proof of ownership based on certificateless signature(PoW-CLS)scheme.Combing the ECL-PRE scheme with PoW-CLS scheme which were mentioned above,we proposed the CDD-CLC scheme.The construction process of the scheme was clarified systematically.Then we analyzed the security of the scheme,compared it with other cloud deduplication schemes in communication and computing consumption,and simulated these sub-schemes by using JPBC to prove the advantages of the scheme in performance.Different from the existing schemes,the certificateless cryptography technology applied in this thesis solved the problem of certificate management and key escrow.ECL-PRE achieved data deduplication based on ciphertext.PoW-CLS improved the efficiency of the proof of ownership(PoW)and solved offline brute force dictionary attacks.