Being IC curd which is jointed by IC curd and the authentication manner

摘要

PROBLEM TO BE SOLVED: To provide an IC card capable of authenticating an external device with higher security without complicating structure and without complicating processing. SOLUTION: An external device transmits key data to an IC card, and requests key/pin collation processing. When collation coincidence is obtained once, the external device transmits dummy key data afterwards, and requests key/pin collation processing, and intentionally generates the collation non- coincidence. When the collation non-coincidence is generated the prescribed number of times, the external device transmits the correct key data again to the IC card, and requests key/pin collation processing. When the second collation matching is obtained, the IC card compares the number of times of the collation non-coincidence counted inside with the correct number of times of the collation non-coincidence preliminarily stored as authentication sequence information, and when they are coincided, the external device is authenticated.