METHOD AND SYSTEM FOR AUTHENTICATION AND AUTHENTICATION PROCESSING PROGRAM RECORDING MEDIUM

摘要

PROBLEM TO BE SOLVED: To exclude any illegal access by identifying any legal access with a small calculation quantity in single sign on type authentication for permitting plural times of access by single user authentication. SOLUTION: Secrecy information 4 is shared by a client means 1 and an authentication server means 2. The authentication server means 2 issues an authentication ticket 5 including collation information obtained by performing an irreversible arithmetic operation (f) on the secrecy information 4 (n) times. The client means 1 indicates this authentication ticket and presentation information obtained by performing an irreversible arithmetic operation (f) on the secrecy information 4 (n-k) times to a permission server means 3. The permission server means 3 performs the irreversible arithmetic operation (f) on the presented information (k) times, and checks whether or not this presented information matches the collation information. In this case, (k) is increased from 1 to (n) so that the authentication ticket 5 can be used for the maximum (n) times of access without calculating the next presented information from the past presented information.