An ID (MID) is attached to each individual optical disk, and content is encrypted with a Content-Key and registered. In addition, a system server device maintains a Client ID of a client terminal device, HDD-ID of a hard disk drive (HDD), and MC-ID of a memory card respectively held as user entry information. When the user wants to copy the content, together with the optical disk MID, the MC-ID is sent to the system server side. The system server device identifies the user by referencing the MC-ID in the user entry information, and returns a Content-Key, which is used when encoding content. On the user side, content stored in the optical disk is decrypted using the returned Content-Key and copied to the HDD. Accordingly, copying of content is allowed only for an authorized user who is the lawful owner of the storage media.