Method and apparatus for discouraging duplication of digital data
US6765739B2 · kind B2 · utility
6Cited by
15References
31Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 18, 2002 |
| Grant date | Jul 20, 2004 |
| Priority date | — |
| Expiry date | Feb 22, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/00579
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus for creating a machine-readable medium such as a CD or a DVD disc is disclosed. The disc includes encoded copy protection data that, when decoded and re-encoded, produces a tracking prevention sequence of bits that causes a duplicate disc (containing the re-encoded copy protection data) to temporarily lose tracking. The temporary loss of tracking is utilized to render the duplicated disc unusable by placing key data immediately following the encoded copy protection data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.