| 摘要 |
When recording a program on a recording medium of the optical disk or magnetic tape type, the program signal INF is encoded 1 before being registered 2 on the recording medium RC or a material for its manufacture. During playback of the recording medium by means of a common playback arrangement 4 for the particular type of recording medium, the program signal CINF played back is decoded 5 by using decoding information which is obtained from the user's personal data medium ID. At the same time as the decoding, a personal identification information is introduced into the decoded program signal DINF. The personal identification information is introduced preferably in such a way that it is not noticeable when playing back the program signal with the help of a common playback machine. Playback of the recording medium requires access to necessary decoding information, which is assumed to be secret and which is temporarily saved on the personal data medium. This necessitates use of the personal data medium, whereby the personal identification information is necessarily introduced into the decoded program signal. When transferring the decoded program signal to a recording medium of the same or different kind, the personal identification information will always end up on the copy thus produced. With the help of the personal identification information and data stored in conjunction with the obtaining of the personal data medium, such a copy can be traced back to a particular person. This provides protection against unauthorised copying of pre-recorded media. <IMAGE> |
