COMMUNICATION SYSTEM, TERMINAL, REPRODUCTION PROGRAM, RECORDED MEDIUM ON WHICH REPRODUCTION PROGRAM IS RECORDED, SERVER DEVICE, SERVER PROGRAM, AND RECORDED MEDIUM ON WHICH SERVER PROGRAM IS RECORDED

摘要

Reproducing means of a general-purpose computer (1) reproduces content data only when the device ID included in the content data agrees with the device ID of the reproducing device used to reproduce it. If the device ID is changed, the general-purpose computer (1) downloads a restoring program for restoring the device ID to the original one from a restoring program generating server (2) so as to restore the device ID. Thus, for example, the general-purpose computer (1) in a communication system can restore the device ID even if the device ID is changed because of re-installation of an OS or a reproduction program.