| 摘要 |
PROBLEM TO BE SOLVED: To prevent from being exploited, even by plural users at the time of utilization use qualification. SOLUTION: A verifying device 10 transmits check information C≡r<e> mod n and a modulus (n) of a public key to a certifying device 20. The certifying device 20 retrieves an auxiliary certification information (t) corresponding to the public key, and applies unidirectional function h(., .) to the public key modulus (n) and secret information dU held by the certifying device 20 for calculating h(dU, n). This value is multiplied by the auxiliary certification information (t) for calculating th(dU, n), and the check information C is powered by this result so that a response information R≡C<th(d> U,<n)> can be generated, and returned to the verifying device 10. The verifying device 10 checks whether or not R≡r mod n is established for the response information R received from the certifying device 20. If the verification expression has been established, it is determined that a use qualification exists. |
