SERVICE PROVIDING SYSTEM, SERVICE UTILIZATION DEVICE, SERVICE PROVIDING DEVICE, SERVICE RELAY DEVICE, AUTHENTICATION METHOD, AUTHENTICATION PROGRAM, AND RECORDING MEDIUM FOR THE PROGRAM

摘要

At the initial authentication, a portable telephone (service utilization device)(10) sends non-encrypted authentication information (user ID, password) inputted by a user to a server (service providing device)(20), and the server (20) performs authentication processing based on the non-encrypted authentication information received from the portable telephone (10). Then, when the authentication processing is succeeded, the server (20) encrypts the authentication information and returns the result to the portable telephone (10). The portable telephone (10) memorizes the encrypted authentication information received from the server (20). After that, when service is requested to the server (20) the next time onward, the portable telephone (10) sends the encrypted information memorized as above to the server (20), and the server (20) decrypts the received encrypted information to perform authentication processing. In a service providing system including both the service utilization device and the service providing device for providing service to the service utilization device, burden on a user performing input operation of authentication information is reduced and security on authentication information can be enhanced.