With the development of cloud computing,it has become a trend for organizations and individuals to store data on encrypted form in the cloud.In order to search ciphertext with different public key encryption,the concept of equality test encryption is proposed.In this system,the authorized user can compare the ciphertext directly and judge whether the ciphertext contains the same plaintext without decrypting the ciphertext,so it will not expose any plaintext information and guarantee the security of the data.At the same time,the user's protection of the privacy has been completed.This paper focuses on the study deeply of equality test encryption scheme,the more practical encryption scheme of equality test is proposed.The main contribution are as follows:(1)Combined with identity-based encryption scheme and the encryption scheme of filtered equality test,an identity-based encryption with filtered equality test scheme is proposed.Firstly,the background,system model,formal definition and security model of the scheme are given.Secondly,it is proved that the proposed scheme is one-way secure against the chosen identity and ciphertext attack based on the computational bilinear Diffie-Hellman assumption in the random oracle model.Finally,the performance analysis shows that the proposed scheme not only has the filtering function,but also solves the certificate management problem.At the same time,the computational cost increases linearly with the increase of the number of messages and the communication overhead also obtains obvious advantages when the number of messages is fixed.(2)Combined with certificateless encryption scheme and the encryption scheme of flexible authorization equality test,an certificateless encryption with flexible authorization equality test scheme is proposed.Firstly,the background,system model,formal definition and security model of the scheme are given.Secondly,it is proved that the proposed scheme is one-way secure and indistinguishable secure against the chosen ciphertext attack based on the decision bilinear Diffie-Hellman assumption in the random oracle model.Finally,the performance analysis shows that the proposed scheme not only has the flexible authorizationfunction,but also solves the key escrow problem.At the same time,the proposed scheme has lower computational cost in the testing phase and shorter ciphertext length. |