CIPHERTEXT COLLATION SYSTEM, METHOD AND RECORDING MEDIUM

摘要

The problem of the present invention is to prevent the determining of whether two pieces of registered data are of the same input data. In a data registering phase, input data to be concealed is encrypted by using a secret key and secret information, registration data is generated from the encryption data and a verification key by calculating encryption data, and the registration data is stored as a registration template in a storage unit together with an identifier for uniquely specifying the registration data. In a ciphertext collating phase, a data collation request obtained by encrypting input data to be collated is generated by using a random number and the secret information, a determined result is outputted by collating the registration template stored in the storage unit with the data collation request, a collation result which includes a part or the entirety of the registration template corresponding to the determination result is outputted, data is restored from the collation result, and the restored result is outputted.