QUALIFICATION AUTHENTICATION METHOD USING VARIABLE AUTHENTICATION INFORMATION

摘要

PROBLEM TO BE SOLVED: To realize a qualification authentication method using variable authentication information in a simple and small program size by extremely reducing an amount of processing to be executed by a person to be authenticated and a for each authentication phase and to provide a method for carrying out safe authentication which resists eavesdropping on a communication path and foul operation of information in a communication path. SOLUTION: A person to be authenticated calculates authentication data of this time and authentication data of the next time based on a random number, a user ID and a password by using a unidirectional function, codes them so that any person excepting a person to be authenticated can not decode it in a form relating both parameters of this time and the next time with each other by using exclusive OR. They are sent to an authenticator together with a user ID of a person to be authenticated himself. A authenticator received the three pieces of information from a person to be authenticated, compares a correctness recognition parameter calculated by using unidirectional function based on authentication data of this time and an authentication parameter registered in an authentication phase of the last time. If they coincide with each other, authentication of this time is judged as realized and authentication data of the next time is registered as an authentication parameter of the next time.