Method for securing system protected by a key hierarchy
US6222923A · kind A · utility
127Cited by
2References
10Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Dec 15, 1997 |
| Grant date | Apr 24, 2001 |
| Priority date | — |
| Expiry date | Dec 15, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/606
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for securing a system protected by a predefined hierarchy of cryptographic keys, and in particular, for securing a pay TV system, against unauthorized users. An individual cryptographic key assigned to a dishonest customer is determined by forming the intersection of at least two predefined subsets formed at different points in time and pertaining to the same hierarchical level.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.