1. Field of the Invention
The present invention relates to an identification-information recording system which is capable of, when a master optical disk with identification information recorded by a recording unit is manufactured, preventing this recording unit from being wrongly used by monitoring the recording unit's recording of the identification information using a management unit via a network. It also relates to a management unit, a recording unit and a recording control circuit for the same purpose.
2. Description of the Background Art
In recent years, the capacity of an optical disk has been increasingly larger. Hence, for example, in a Blu-ray disk, high-vision contents having a high-quality image can be recorded for four hours or more, and thus, it is expected as a new distribution medium of high-quality contents. On the other hand, as the optical-disk technology makes advances, a grave disadvantage arises in that copyright is violated. Particularly, it is impossible to capture the actual situation of a manufacturer who copies an optical disk distributed on the market to manufacture its pirated edition. This hinders its copyright holder from taking effective countermeasures. Thereby, copyrighted articles cannot be soundly distributed using optical disks.
Therefore, a technique is disclosed in which identification information is recorded onto an optical disk so that a piratical manufacturer cannot make a copy (e.g., refer to Japanese Patent Laid-Open No. 2001-357533 specification). In this method, contents to be recorded onto an optical disk are encrypted beforehand, and the edge position of a record mark formed on the optical disk is displaced in its tangential direction by design. Or, by a special recording method such as displacing the record mark in the radial direction, key information on the encrypted contents is recorded. Accordingly, a piratical manufacturer who is not given how to read such key information is not authorized to read this key information. This helps prevent a false disk from being manufactured.
According to the above described prior art, a copy of a legitimate disk can be prevented from being made to manufacture an illegal pirated edition. However, in the recent optical-disk manufacturing situation, a copyright owner is not necessarily a person who produces a master optical disk. Hence, in the above described special recording method, if a manufacturer of a master optical disk who can record key information does misconduct, that cannot be restrained. Besides, a theatrical movie itself may be filmed using a digital video camera or the like, and then, an optical disk can be manufactured and distributed based on the filmed contents. Such a wrongdoing cannot be prevented, either.
In either case, a mastering service manufacturer who secures contents falsely and produces a master optical disk using the contents needs to be identified. If such a manufacturer cannot be restrained from manufacturing the master optical disk, no such misconduct as described above cannot be restricted.