When a user activates an app, user authentication by a PIN code or the like is first executed. When the user authentication is successful (that is, when it is confirmed that a party operating the app is a user), function limitation of the IC chip is released and a mode in which a function provided by the IC chip can be used is set. The app creates an electronic signature with a private key using the function of the IC chip. When the electronic signature and the user ID are sent to a server of an online service, the server verifies the electronic signature using the corresponding electronic certificate. When the user ID is confirmed to be a user ID sent from a valid user, the user is permitted to use the online service.