Key update mechanism
US7889862B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 2006 |
| Grant date | Feb 15, 2011 |
| Priority date | — |
| Expiry date | Nov 17, 2029 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N7/1675
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A memory stores data in an encrypted form. A modifiable register stores a memory address, a0, defining a boundary separating the memory into two regions. The lower region stores data encrypted using a key B, and the upper region stores data encrypted using a different key A. Data stored on the boundary address is encrypted using key A. Accordingly, when data is read from a memory address a, key A is used to decrypt the data if a≧a0, and key B is used if a<a0. However, when data is written to a memory address a, then key A is used to encrypt the data if a≧a0+1, key B is used if a<a0+1. When data is written to the boundary address, a0, the position of the boundary is caused to increase by one unit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.