System for updating an authorization memory
US5680457A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1995 |
| Grant date | Oct 21, 1997 |
| Priority date | — |
| Expiry date | Apr 25, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/658
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A subscriber terminal includes a digital conditional access module receiving a transport bitstream comprising a plurality of multiplexed conditional access and product packets. Selected ones of the conditional access packets are addressed to respective terminals and include an encrypted new decryption key code, an encrypted authorization bit map and an authorization list range delete code. The conditional access packets are decrypted by the conditional access modules of respective addressed terminals, the decrypted new decryption key code being stored for subsequent use by the conditional access module, the decrypted authorization bit map being used to refresh the authorization bit map memory of the module and the decrypted delete code being used to delete a specified range of authorization codes from the authorization list memory of the module.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.