| 摘要 |
PURPOSE: To identify whether it is an original disk or an unjust copied disk by making a recording position of a CAV(constant angular velocity) area a title peculiar value corresponding to the security data recorded in a system area. CONSTITUTION: A CD-ROM provided with the CAV area at every title is formed, and in a next step, a function deciding the number and the recording position of the CAV area, a linear velocity, etc., from a key code is provided in a CD- ROM reproducing device (13). Then, the CD-ROM is loaded on the reproducing device, and further, the key code is detected, and the positional information of respective CAV areas are generated using the key code. In the step 17, respective CAV areas are retrieved based on the positional information of the CAV areas, and when respective linear velocities are the CAV, the reproduction of the CD-ROM is allowed, and the reproduction is prohibited when not the CAV. |
