Signal encryption apparatus for generating common and distinct keys
US5115467A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 23, 1991 |
| Grant date | May 19, 1992 |
| Priority date | — |
| Expiry date | Jan 23, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/26606
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Signal encryption apparatus is provided for generating a common key and a distinct key from the same common secret generating key. A generating key is combined with common parameter data to provide a common intermediate key. The common intermediate key is used to produce a common key. The generating key is also combined with distinct parameter data to provide a distinct intermediate key. The distinct intermediate key is used to produce a distinct key. The system has particular applicability to the provision of category and program keys for use in a satellite television scrambling system. The generating key is used to produce the same category key at all uplinks, and different program keys at each uplink.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.