Patent · US Expired

Digital computer system for executing encrypted programs

US4847902A · kind A · utility

78Cited by
10References
7Claims
0Family size

Assignee

Inventor

Key dates

Filing dateFeb 10, 1984
Grant dateJul 11, 1989
Priority date
Expiry dateFeb 10, 2004

Classification

  • Technology area (CPC G)Physics
  • CPC primaryG06F12/0875
  • WIPO fieldComputer technology
  • WIPO sectorElectrical engineering

Abstract

A digital computer system adapted for executing a set of instructions including at least one encrypted instruction. The system includes a main memory for storing the instructions, a cache memory for storing selected instructions with a relatively fast access time, a selectively operable decryption system for decrypting selected encrypted instructions from the main memory, and a central processing unit. The system is adapted so that the program stored in the main memory may be executed by the central processing unit. To this end, the decrypted instructions are decrypted only during execution when those instructions are transferred from the main memory to the cache memory so that plaintext versions of those encrypted instructions exist only in the cache memory in response to requests by the central processing unit while executing the program.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.