AUTHENTICATION SYSTEM, INFORMATION TERMINAL, SUBSCRIBER IDENTIFIER ISSUING DEVICE, PUBLIC KEY REGISTERING DEVICE, AUTHENTICATION METHOD, PROGRAM, AND STORAGE MEDIUM

摘要

PROBLEM TO BE SOLVED: To provide an authentication system and an authentication method capable of securing security tantamount to PKI (public key infrastructure) easily compared to PKI. SOLUTION: An enormous number of information terminals (clients) can be authenticated easily by conducting subscriber authentication using the telephone number of an information terminal 10, to which impersonation is extremely difficult. A subscriber identifier, which is difficult for speculation of the telephone number based on the authenticated telephone number, is issued, and a pair of this subscriber identifier and a public key generated by the information terminal 10 can be registered in an open public key database 300. Accordingly, a web server 50 can verify easily legitimacy that the information terminal 10 owns surely a secret key S, which forms a pair with a public key P associated with the subscriber identifier.