AUTHENTICATION SYSTEM, AUTHENTICATION METHOD, AND AUTHENTICATION PROGRAM

摘要

PROBLEM TO BE SOLVED: To provide an authentication system, an authentication method, and an authentication program which suppress an increase in installation cost and enhance security.SOLUTION: In an authentication system 1, a user terminal 10 generates a response value by a challenge random number received from an authentication server and a first authentication code, then generates the encrypted response value by a second authentication code and transmits it to the authentication server 20. The authentication server 20 notifies the user terminal 10 of an authentication result of comparison between a first verification response value into which the encrypted response value is decrypted and a second verification response value generated by the random number and the first authentication code.