SINGLE SIGN-ON SYSTEM, INFORMATION TERMINAL DEVICE, SINGLE SIGN-ON SERVER, SINGLE SIGN-ON UTILIZATION METHOD, STORAGE MEDIUM, AND DATA SIGNAL

摘要

There is provided a single sign-on server including a receiving unit that receives a server connection request which is transmitted from a client for a service provision server that provides a service; an establishing unit that transmits, to a service provision server identified from the received server connection request, an authentication request that contains at least an address for use in communication with the service provision server and authentication information set for the single sign-on server, undergoes user authentication, and establishes a session with the service provision server; a disabling unit that performs disabling processing of the address which is being used in communication with the service provision server; and an information transmission unit that transmits session information on the session established with the service provision server, the session information containing at least the address, to the client that transmits the server connection request.