Patent ID: 8819796

Claim:
An authentication system including a user terminal and an administrative server, the authentication system performing user authentication based on login information that includes a user ID and a password for identifying a user, the authentication system comprising: a registration accepting unit for accepting registration of a type of a login image that composes an authentication button for initiating the user authentication when the login information is registered, the registration accepting unit being arranged in the administrative server; a login image obtaining unit for generating an authentication page on the user terminal in response to a request from the user terminal, the authentication page displaying a plurality of operation buttons that include an authentication button composed of the login image accepted by the registration accepting unit and dummy buttons composed of images different from the login image, the login image obtaining unit being arranged in the administrative server; an authentication page displaying unit for displaying the authentication page in a state where the login information has been automatically input into an entry field of the authentication page generated by the login image obtaining unit, the authentication page displaying unit being arranged in the user terminal; a login image determining unit for determining a type of an operation button selected on the authentication page by a user of the user terminal, and for transmitting the login information being input into the entry field to the administrative server in a case in which the operation button thus selected is the authentication button, the login image determining unit being arranged in the user terminal; and an authenticating unit for performing the user authentication, based on determining whether the login information is correct, the authenticating unit being arranged in the administrative server.