Firmware encryption for microprocessor/microcomputer
US5386469A · kind A · utility
46Cited by
2References
16Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1993 |
| Grant date | Jan 31, 1995 |
| Priority date | — |
| Expiry date | Aug 5, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/04
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A mask value generator is used to produce a mask value for deencrypting encrypted instructions from a memory. This encryption mask generator can produce a encryption mask value from a seed value and a program counter value. The seed value can stored in a memory outside the core microprocessor. The encryption mask value can be used to deencrypt instructions in an "exclusive or" logic section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.