Research On Distributed Attribute-Based Encryption For Mobile Cloud

With the development of cloud computing and the growing share of mobile users,mobile terminals can use cloud computing technology to expand computing resources and storage resources.As a combination of cloud computing technology and mobile terminal products,mobile cloud technology has become the focus of research in recent years.However,the mobile cloud environment has serious data security problems and user privacy disclosure problems.DCP-ABE scheme has a strong scalability,very suitable for use in mobile cloud environment.DCP-ABE scheme on the one hand can ensure data confidentiality and can achieve fine-grained data access control,on the other hand can protect the user's privacy.In recent years,researchers has made a lot of research results in the field of DCP-ABE.However,most of the DCP-ABE schemes have the disadvantages of low efficiency,excessive granularity of revocation mechanism,and leakage of user privacy.Aiming at the shortcomings of the DCP-ABE scheme,this paper proposes a DCP-ABE scheme suitable for mobile cloud which supports attribute revocation and privacy protection in the standard model.The scheme significantly improves the efficiency by introducing offline/online encryption,verifiable outsourcing computation of modular exponentiations and outsourcing decryption.The main work of this paper includes the following two aspects:Firstly,this paper improves the DCP-ABE scheme proposed by Horváth,realizing a DCP-ABE scheme suitable for mobile cloud in the standard model.In the aspect of the revocation mechanism,the scheme realizes the immediate revocation of the attribute level by improving the revocation mechanism in the Horváth scheme,thus realizing the user's fine-grained access control to the ciphertext.In the aspect of efficiency,the scheme first introduces offline/online encryption to transfer most of the bilinear pairing operations to the offline encryption stage.Then,this scheme introduces the verifiable outsourcing scheme for batch modular exponentiation calculation protocol to outsource most of the exponential calculation to the cloud server.Mobile clients only need some simple modular multiplication operations.Finally,this scheme introduces the outsourcing decryption,significantly reducing the computational burden of user decryption operation.Secondly,in order to make the DCP-ABE scheme suitable for mobile cloud support privacy preserving,this paper designs an anonymous key generatio n protocol.The protocol can successfully obtain the user's private key,while protecting the user's GID information and attribute set information.Finally,this paper replace the key generation algorithm in the DCP-ABE scheme suitable for mobile cloud with the anonymous key generation protocol,realizing complete protection of user privacy.