| 摘要 |
PURPOSE:To shorten time required for a subscriber authentication processing in a communication processing mode after the second processing. CONSTITUTION:A communication equipment 10 of a subscriber terminal and a communication processing unit 20 of an exchange certify the communication equipments in the first communication processing mode with the same method as the conventional method but the communication equipment 10 stores a signal Kb ciphering a random number by an authentication key Ka of the communication processing unit 20 and a signal Ki ciphering the random number by an authentication key Ki used at that time and the communication equipment 10 sends a signal Kb used last time to the communication processing unit 20 in the second communication processing mode at the time of a service request. Then, the communication processing unit 20 decodes the received signal Kb, defines it as an authentication key Kc this time and sends a signal ciphering the random number by this key, the signal Kb ciphering the random number by the signal Kb and the random number to the communication equipment 10, and the communication equipment stores these data, decodes the stored signal Ki last time with the authentication key Ki last time, defines it as the authentication key Kc, ciphers the received random number and sends it to the communication processing unit 20. At the unit 20, this is received and decoded and when the result is coincident, service is permitted. |
