Method for Managing Authorization for Accessing Homomorphic Ciphertext Using Identity-Based Encryption

摘要

The homomorphic encryption text calculation method according to the present invention is performed in an environment including a data providing server holding user-based information, a data operation server, a user terminal, and an identity-based encryption key generation server, the method comprising: A first encryption value (a value obtained by encrypting the user-based information (D _i ) of the data providing server (P _i ) by the operation server, the secret key (K _{i ) of the data operation server} ) and the public key (K _i ) generated based on the user identity information (IDj) ) as the second encryption value ( ) a first step of receiving from the data providing server; The data operation server uses the user's homomorphic encryption public key ( ), The secret generated on the basis of the user identity (ID _j) key ( ) of the first homomorphic encryption value ( a second step of receiving ) from the key generation server; The data operation server recrypts the second encryption value to the first isomorphic encryption value to obtain a second isomorphic encryption value ( ) a third step of obtaining; The data operation server decrypts the first encrypted value into the second isomorphic encryption value, and the third isomorphic encryption value ( ) a fourth step of obtaining; The data operation server performs a predetermined operation on the third isomorphic encrypted value, and the result is a fourth isomorphic encrypted value ( ) a fifth step of calculating; and a sixth step of transmitting, by the data operation server, the fourth isomorphic encryption value to the user terminal.