Secure lock mechanism based on a lock word
US7398554B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 2, 2002 |
| Grant date | Jul 8, 2008 |
| Priority date | — |
| Expiry date | Mar 12, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F21/71
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
One or more lock words in a non-volatile memory with write ability correspond to lockable features of a protected system including the memory. A lockable feature should be locked when the corresponding lock word has a value equal to one of a limited number of predetermined locking combination(s). The locking combination(s) are selected so as to minimize the probability of the lock word waking up from manufacture with a value equal to one of the locking combination(s). In order to detect whether allowable usage of a lockable feature should be at a predetermined locked or unlocked level, multi-sampling of the corresponding lock word value is performed. If there is variation among the sampled values of the lock word, a malicious attack is identified. In one preferred embodiment, the multi-sampling occurs upon power up reset of the protected system and if a malicious attack is identified, the protected system is kept in reset.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.