Homomorphic data decryption method and apparatus for implementing privacy protection
摘要
說明書
According to a third aspect of the one or more implementations of the present specification, a homomorphic data encryption apparatus for implementing privacy protection is provided, and includes the following: a public key acquisition unit, configured to obtain public key pk={N, h} corresponding to a target user, where h is a generator of a predetermined cyclic group with a size of k in random number space Z*N, a length of k is i bits, a length of N is n bits, and i<<n; a random number selection unit, configured to select random number r, so that hr belongs to the predetermined cyclic group; a data processing unit, configured to process to-be-encrypted data m corresponding to the target user by using public key pk and random number r, to generate homomorphic ciphertext c=(1+N)m·(hr mod N)N=(1+N)m·(hN mod N2)r mod N2; and a ciphertext providing unit, configured to provide homomorphic ciphertext c to the target user, where homomorphic ciphertext c can be decrypted by the target user by using private key sk to obtain data m, a value of private key sk is α=a·k, and a is a predetermined non-zero value.
