Optical disc copy management system
US6535858B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1998 |
| Grant date | Mar 18, 2003 |
| Priority date | — |
| Expiry date | Aug 26, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2211/007
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to a method of obtaining a copy protected optical record carrier carrying information in different blocks, a method of accessing such a copy protected optical record carrier and such an optical record carrier itself. Access devices for optical carriers return different results when retrieving blocks, which contain incorrect address data in the corresponding subcode fields. A copy protection key will be implemented during manufacture of an optical record carrier by modifying the subcode address information of a predetermined pattern of blocks. It is normally not possible to copy incorrect address data onto an optical record carrier, since the address data will be newly generated during the copy process. Therefore, such a key can be utilized to distinguish between an original disc and a copied or non original disc. The key is preset before manufacturing of the optical record carrier itself and can therefore be used to encrypt the data stored on the optical record carrier. Upon accessing of the data, first the key is extracted from the optical record carrier and then the data can be decrypted utilizing this key.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.