Unauthorized use prevention method for optical disks, optical disk having unauthorized use prevention function, and optical disk apparatus
US5418852A · kind A · utility
121Cited by
6References
53Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 17, 1993 |
| Grant date | May 23, 1995 |
| Priority date | — |
| Expiry date | Mar 17, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2020/1259
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a method for preventing unauthorized use of a recording medium having a user accessible area and a user inaccessible area, first information is read from the user inaccessible area of the recording medium. The first information is compared with second information concerning a true recording medium (lawfully produced copy). It is then concluded that the recording medium is the true recording medium when the first information corresponds to the second information.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.