Amount information stored in an IC chip installed in a portable terminal has been encoded, and no key is contained in the same terminal for protection against unauthorized use. On the other hand, in order to allow the information to be viewed even offline, a portion of the information can be displayed by a specific application. After a viewer application is downloaded from a service provider, followed by mutual authentication with the IC chip, the application is enabled on the terminal, and the extent viewed is registered. Therefore, the amount information stored in the IC card or IC chip can be displayed even in an offline environment.