Microprocessor that facilitates task switching between multiple encrypted programs having different associated decryption key values
US8719589B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 2011 |
| Grant date | May 6, 2014 |
| Priority date | — |
| Expiry date | May 5, 2032 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/20
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A microprocessor includes a storage element having a plurality of locations each storing decryption key data associated with an encrypted program. A control register field (may be x86 EFLAGS register reserved field) specifies a storage element location associated with a currently executing encrypted program. The microprocessor restores from memory to the control register a previously saved value of the field in response to executing a return from interrupt instruction. A fetch unit fetches encrypted instructions of the currently executing encrypted program and decrypts them using the decryption key data stored the storage element location specified by the restored field value. A kill bit associated with each storage element location may be employed if the location is clobbered because more encrypted programs are multitasked than available locations in the storage element, in which case an exception is generated to re-load the clobbered decryption key data in response to the return from interrupt instruction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.