Disclosed is a system (100) composed of a main device (300) and a recording medium device (400). The main device includes: a reception unit (300) that receives a digital work from an external distribution server (200); an internal storage area for storing the digital work; a playback unit that plays back the digital work; a unique information storage area for storing information that is unique to the main device; an encryption unit that encrypts the digital work using the unique information; a decryption unit that decrypts, using the unique information, the encrypted digital work having been read from the recording medium device; a write unit that writes the encrypted digital work into the recording medium device which is portable; and a read unit that reads the encrypted digital work from the recording medium device. <IMAGE>
