DEVICE AND METHOD FOR VERIFYING SIGNATURE

摘要

PROBLEM TO BE SOLVED: To confirm that a public key certificate used for the verification is surely not invalid at the time of verifying a signature. SOLUTION: This device (1) confirms that the public key certificate to be used for verifying a signature is not invalidated; (2) verifies the signature by using the public key, and registers the public key certificate identification information, the date of issue of the next CRL (invalidated public key certificate list), and the date of the signature verification in a state management table according to each processing number; and (3) when the next CRL issue date has passed, the device confirms that each certificate identification information was not invalidated on the date when each information was used for the signature verification.