Copyright protection system, recording device, decryption device, and recording medium

摘要

A copyright protection system (100) includes a recording device (10) and a reproduction device (30). The recording device (10) writes encrypted content (15), an encrypted content key (12,13) for decrypting the encrypted content (15), and license information (16) on a recording medium (20) on which a unique media number (21) has been recorded in an unrewritable state. The license information (16) is generated using both the media number (21) and the encrypted content key (13), and therefore reflects both values. The reproduction device (30) reads the media number (21), the encrypted content key (13,23), and the license information (16,22) from the recording medium (20), and judges (36) whether the license information (16,22) reflects both the media number (21) and the encrypted content key (13,23). Only if the license information (16,22) reflects both values, the reproduction device (30) decrypts the encrypted content key (32,33), and decrypts the encrypted content using the content key (12,13). In this way, the copyright protection system (100) allows only original recording media (20) to be reproduced, and prohibits reproduction of copy recording media.