FALSE ALTERATION PREVENTION SIGNATURE METHOD

摘要

A false alteration prevention signature device comprises a feature extraction unit (33) that extracts a feature value representing the feature of image data according to an instruction from an authenticator who has authenticated display data; an encryption/decryption unit (35) that encrypts the feature value using an encryption key a paired with an identifier to generate encrypted data, and decrypts the encrypted data into the feature value; a medium writing unit (34) that adds the identifier and the encrypted data to a re-writable medium; and a controller (37) that checks if the decrypted feature value matches the feature value extracted from image data generated by reading display data.