AUTHENTICATION SYSTEM, AUTHENTICATION DEVICE, AUTHENTICATION DATA PRODUCING DEVICE, AND AUTHENTICATION METHOD

摘要

Upon receiving an encipherment command, an enciphered authentication data generation circuit generates an enciphered authentication data based on a basic authentication data including a random number portion using an encipherment rule. The encipherment rule changes according to the number of supplied encipherment commands. A transmission circuit 7 transmits the enciphered authentication data. A reception circuit 9 receives the enciphered authentication data transmitted from a second device 300. A prohibition command output circuit 11 determines whether the enciphered authentication data transmitted from the second device 300 matches with an enciphered authentication data that would be generated if the same number of encipherment commands were supplied to an enciphered authentication data generation circuit of a first device 200, and outputs a prohibition command to prohibit a transmission of the data to be transmitted when the determination result is negative.