SAFETY REINFORCEMENT METHOD, SAFETY REINFORCEMENT SYSTEM, SAFETY REINFORCEMENT DEVICE, VERIFICATION DEVICE, AND PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide a technology for reinforcing safety against an association key attack capable of reinforcing the safety of an already used secret key.;SOLUTION: A secret information generation part 123 generates secret information. A temporary key generation part 124 generates a temporary key by using the secret information, and generates a key ciphertext by encrypting the input secret key information by the temporary key. A first encryption part 125 and a second encryption part 126 obtain a ciphertext having a specific correspondence relation with the secret information. An output part 128 generates auxiliary information including the ciphertext and the key ciphertext. A verification part 132 determines whether or not the auxiliary information has the correspondence relation with the secret information. A temporary key control part 133 generates the temporary key by using the secret information when the auxiliary information has the correspondence relation with the secret information. A key control part 135 obtains the key information by decrypting the key ciphertext by using the temporary key. In this case, it is difficult to specify related auxiliary information having the correspondence relation with related secret information different from the secret information from the auxiliary information.;SELECTED DRAWING: Figure 2;COPYRIGHT: (C)2016,JPO&INPIT