Protection of a program waiting to be executed in a memory used by a microprocessor

摘要

A method for authorizing an access to a table of address correspondence between a multitask CPU and at least one memory containing several programs, consisting of calculating, on each task change of the CPU, a signature of at least part of the program instruction lines, and checking the conformity of this signature with a signature recorded upon previous execution of the involved program.

主权项

1. A method, comprising:
executing, by a multitasking processor in a foreground, a first program module, the executing including accessing a table of address correspondence between the multitasking processor and a memory storing instruction lines of multiple program modules; transitioning from foreground execution of the first program module by the multitasking processor to foreground execution by the multitasking processor of another program module of the multiple program modules; calculating a first signature based on at least some instruction lines of the first program module stored in the memory; and transitioning to foreground execution of the first program module, the transitioning including:
calculating a second signature based on the at least some instruction lines of the first program module stored in the memory;comparing the first signature to the second signature; andpreventing execution of instruction lines of the first program module stored in the memory by the multitasking processor based on the comparing.