Scrambling and unscrambling method for composite video signals and implementing device
US5208856A · kind A · utility
54Cited by
6References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 23, 1991 |
| Grant date | May 4, 1993 |
| Priority date | — |
| Expiry date | Dec 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/4623
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The method of the invention consists, during the transmission of composite video signals, in the inclusion therein of series of access messages (ECM1, ECM2) and, during the unscrambling, carried out using a chip card reader whose chip card comprises encoded digital data, in using an interactive method of identification of a digital signature.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.