Multiple purpose integrated circuit
US8060732B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 13, 2007 |
| Grant date | Nov 15, 2011 |
| Priority date | — |
| Expiry date | Oct 14, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F2221/2105
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An integrated circuit is operable to execute boot loader code and a boot code from external memory. To provide security so that the CPU does not execute malicious codes, the circuit resets in a restricted mode in which only certain functional units may be connected. In the restricted mode the CPU is only able to fetch boot code from an external memory for transfer to an internal memory. A hash function operates on the fetched boot code to determine whether it is authentic and, if it is determined that the code is authentic the circuit is reset to an unrestricted mode to continue executing from the boot code now stored in the internal memory. Further security is provided by a watchdog timer function which resets the circuit if the boot code is not determined to be authentic within a threshold period of time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.