CP-ABE Solution Based On Time-Release Encryption In Cloud Storage Environment

At present,as an era of data explosion,cloud storage environment not only brings convenience to the storage and the sharing of massive data,but also brings some challenges in data security on concurrently.Among them,the most important research of cloud storage environment is about Access Control Mechanism.However,the traditional access control mechanism relies on trust upon the storage system environment,which is incompetent in an open cloud storage environment.Specifically,in order to ensure the sharing security of mass storage data in cloud storage environment,users are required to encrypt their shared data and store it in the cloud storage platform,at the same time,an effective access control is very essential.In this way,a cryptograph secure sharing mechanism based on CP-ABE(Ciphertext-Policy Attribute based Encryption)emerged.However,in the real-world cloud storage environment,there are still many time-sensitive scenarios.These scenarios,such as the release of movies and TV plays,electronic bidding,online examinations,need an effective and safe sharing mechanism to fulfill their access control requirements.Therefore,how to establish a CP-ABE ciphertext sharing mechanism with time-controlled encryption in a cloud storage environment is the problem that needs to be solved urgently at this stage.In response to the problems mentioned above,this thesis will introduce Timed-Release Encryption(TRE)technology and propose a CP-ABE scheme based on Timed-Release Encryption in cloud storage environment.In this scheme,TRE mechanism is integrated in CP-ABE mode,so that the shared data exists in the form of ciphertext before the set information release time is up.Besides,only after the set release time out,the data receiver can decrypt the encrypted shared data correctly,and the plaintext information then required can be obtained.At the same time,this scheme will solve the user's identity authentication problem by using the user's attribute allocation,and the fake threat of illegal users by adding a user fixed tag into the user's private key.Besides,when the attribute or user right needs to be modified or revoked,the decryption key of the corresponding registered user will also be updated in time.Finally,through theoretical analysis and security verification,this thesis elaborates on the ability of the proposed scheme to resist various malicious attacks in the cloud storage environment.After security analysis,it can be concluded that the CP-ABE scheme which based on time-release encryption in the cloud storage environment proposed in this thesis can effectively resist four common and typical attack behaviors in the cloud storage environment with high security.