Research On Forward Secure Searchable Symmetric Encryption

Searchable symmetric encryption is a cryptography primitive,which enables searching over the encrypted data without decryption.Stefanov et al introduced a new security definition in searchable symmetric encryption called forward security at the conference of NDSS in 2014,and gave an ORAM based forward secure searchable symmetric encryption scheme.In recent years,some research on the attack on searchable symmetric encryption has underlined the necessity of forward security.In the view of efficiency and functionality,this paper focuses on the research of existing forward secure searchable symmetric encryption schemes,and introduces two improved forward secure searchable symmetric encryption schemes.Firstly,on the basis of Diana scheme,we propose a forward secure searchable symmetric encryption scheme supporting batch update.In our proposed scheme,a batch of files containing the same keyword share the same search token,instead of a unique search token for each file.Thus,in the scenario of the update mentioned above,the overhead of updating the search token in our proposed scheme is constant.Our proposed scheme achieves well batch update performance,while keeping the advantage of client storage in Diana scheme.We give the security analysis and simulation experiment.Secondly,considering the problem that existing multi-user forward secure searchable symmetric encryption schemes require a third-party trusted server to participate in the search operation,we propose an improved multi-user forward secure searchable symmetric encryption scheme.Similar to existing schemes,our proposed scheme has two servers: storage server and third-party trusted server,but the third-party trusted server in our proposed scheme only participates in generating parameters and generating secret keys for authorized users.When updating files or searching files,the data owner and authorized user only need to interact with the storage server.We give the security analysis and simulation experiment for the proposed scheme.