The Study On Revocable And Searchable Attribute Based Encryption Scheme For Mobile Cloud Storage

Attribute-Based Encryption(ABE)can be adopted to protect data privacy and achieve fine-grained access control in cloud storage.However,attribute revocation mechanism is a difficulty when apply ABE schemes to practical applications.Besides,how to search over encrypted data is another challenge in cloud storage.At present,with the widespread use of mobile devices,mobile cloud storage technology has become a new application hotspot.Considering in mobile cloud storage environment,most of the computation tasks are executed by mobile devices,the general cloud storage schemes always produce high computation overhead on user side,which not suitable to the mobile environment.However,there are not many solutions for mobile cloud storage.Therefore,it is of great significance to study the data security problem in mobile cloud storage.In this paper,we focus on the attribute revocation and keyword search based on attribute-based encryption in mobile cloud storage.The following two results are obtained: 1)We proposed an efficiently revocable and searchable attribute-based encryption(RSABE)scheme for mobile cloud storage.In this scheme,the user's secrect key is divided into two parts by using the outsource decryption technology,attribute related part is securely delegated to the cloud server as a delegation key.Therefore cloud sever can be delegated to partially decrypt the ciphertext.During the attribute revocation phase,the update of user's delegation key is performed by the cloud server and secret key component that user hold does not need to be updated.In this scheme,the user's storage overload and decryption cost have been greatly reduced,and even does not participate in the secrect key update during the revocation phase.Therefore,the proposed scheme has lower hardware demands for user side,and it is very suitable for mobile cloud storage environment.Finally,the security of the scheme is reduced to the decision bilinear Diffie Hellman problem and the q-parallel bilinear Diffie-Hellman exponent problem.2)We proposed an attribute based encryption with conjunctive keyword search(ABE-CKS)scheme for mobile cloud storage.In this scheme,the user submits multiple keywords trapdoor to request retrieval.For a set of keyword indexes,cloud server could determine whether there is a match between the trapdoor and the indexes without combination of indexes,and can simultaneously achieve fine-grained access control.Therefore,the retrieval efficiency is higher.Because the computing task of the access control is performed by the cloud server,the complexity of the user's decryption operation is controlled under the constant size,so the decryption load is lower.Finally,the proposed scheme is proven to be chosen plaintext attack secure under the general group model.