Method of controlling descrambling of a plurality of program transport streams, receiver system and portable secure device
US7552457B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 12, 2004 |
| Grant date | Jun 23, 2009 |
| Priority date | — |
| Expiry date | Sep 29, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/835
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of controlling descrambling of a plurality of program transport streams received by a receiver system comprises receiving a sequence of messages in a conditional access sub-system (9,10) comprised in said receiver system, each message being associated with one of a number of scrambled program transport streams and representing a request for returning information enabling the associated scrambled transport stream to be descrambled by at least one descrambler module (12) in the receiver system, determining whether messages received within a certain interval are associated with a number of different scrambled program transport streams, and denying at least one of the requests represented by the messages received in the certain interval, if the number of different scrambled program transport streams with which the messages are associated exceeds a pre-determined number.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.