With the rapid development and popularization of cloud computing,a large quantity of user data is encrypted and stored in the cloud in the form of ciphertext,resulting in low data search efficiency.The ciphertext equivalence test technology can effectively compare the ciphertext encrypted by different public keys.Whether it corresponds to the same plaintext to solve the problem.Using this technology,the cloud server can test whether two ciphertexts encrypted with different public keys are generated from the same plaintext when the trapdoor cannot be decrypted.Based on the ciphertext equivalence test technology and the certificateless public key cryptosystem,this paper conducts research and application on the certificateless public key encryption with equality test scheme.(1)A certificateless public key encryption with equality test scheme based on group user authorization is proposed.This scheme adds the function of the group mechanism on the basis of the existing certificateless public key encryption with equality test scheme.In the previous schemes,the tester can test the ciphertext of any user,but in this scheme,the tester can only test the ciphertext of users in the same group.(2)A certificateless signcryption with equality test scheme is proposed.This scheme adds the function of signcryption on the basis of the existing schemes.In the previous schemes can only detect whether the plaintexts corresponding to different ciphertexts are the same,but this scheme can not only detect whether the plaintexts corresponding to different ciphertexts are the same,but also prevent the message from being tampered with.(3)Based on the application of certificateless public key encryption with equality test scheme in electronic medical record data sharing.This technology can compare the ciphertext of electronic medical records and can have application in the electronic medical records to realize data sharing. |