Research On Searchable Encryption Based On CP-ABE Technology

In recent years,with the rapid advance in cloud computing and cloud storage technology,more and more users will store data in the cloud to enjoy high-quality storage,data management and efficient retrieval services.In order to ensure the security and confidentiality of data,users usually store data in the form of ciphertext in the cloud server.However,it is difficult for users to retrieve these ciphertext data.Searchable encryption scheme can achieve secure and efficient data sharing,and support keywords search in ciphertext.At present,searchable encryption has become a hot issue in cloud computing encryption system.In this thesis,the searchable encryption technology based on CP-ABE is studied and two ciphertext-policy attribute-based searchable encryption schemes are presented.The first scheme is to solve problems that key disclosure and attribute revocation funcation is not supported.The access structure of the scheme is based on LSSS linear secret sharing matrix,which not only supports fine-grained access control but also has high computational efficiency.Then the security of the scheme under the general group model is proved.Moreover,the secret key is blinded by a random number before submitted to sever.In the process of attribute revocation,the work of re-encryption ciphertext is completed by the cloud sever.Furthermore,the analysis shows that the security can be proved under the Decisional Linear assumption.Secondly,a CP-ABE based mulit keywords search encryption algorithm is proposed to support multi keywords search.In this scheme,users retrieve multiple keywords at one time,which can improve the retrieval efficiency and accuracy,and redue the computational and communication overhead.The security can be proved under random oracle model.