| 摘要 |
In a first recording area of the disc, main information is recorded using an 8-16 modulation system in the form of pits, and by partially removing multiple radially-extending reflective films, sub-information is recorded in a second recording region using a phase-encoding modulation system. Identification information unique to each optical disc is recorded in the sub-information. The identification information and/or a password is used to access protected parts in the main information. The optical disc is a reproduction type disc. In addition to the optical disc identification information, encryption keys and/or decryption keys may be recorded. |
