Conditional access filter as for a packet video signal inverse transport system
US6671881B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 4, 1996 |
| Grant date | Dec 30, 2003 |
| Priority date | — |
| Expiry date | Dec 4, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/4623
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus in a receiver, for processing transmitted entitlement control information, includes a packet transport processor for selecting signal packets having payloads containing a conditional access payload header and a remaining payload of entitlement data. Respective payload headers include groups of bytes which are coded in a manner to allow or disallow the respective receiver from processing the entitlement data. A conditional access filter preprogrammed with a subscriber specific conditional access codeword examines respective byte groupings of the conditional access header for a match with the subscriber specific conditional access codeword. Only if a match occurs is the processor permitted to process the entitlement data. The entitlement data is thereafter utilized to generate decryption keys for descrambling portions of the transmitted signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.