| 摘要 |
PROBLEM TO BE SOLVED: To make an authentication device hardly estimate a measured value due to acquisition of a random value and to improve the reliability of the authentication device by measuring the key depressing time of one of the both devices when they mutually encipher and decode random numbers to authenticate the opposite device and using the measured value as an initial value to generate the random number. SOLUTION: The random number data which are generated by a portable terminal 2 that has a common enciphering/decoding key are sent to another device such as an IC card 3 or an automatic vending machine 1. The other device which receives the random number data encihpers these data and returns them to the terminal 2. The terminal 2 decodes the received cipher data and compares them with the original random number data. When the coincidence is confirmed between the both data, the device of the opposite party side is decided as a correct device. In such a constitution of this mutual authentication device, the depressing time of a keyboard 212 of the terminal 2 is measured and a random number is generated by using the measured time as an initial value. |
