Patent ID: 7822953
Filing Date: 2010-10-26
Classification: G06F

Abstract:
1. A method for checking integrity of program execution by a circuit, comprising: storing each instruction and instruction argument of a program as data at a memory location in a memory, the memory location identified by a memory address; storing in the memory, with each instruction and instruction argument of the program, a redundancy code which is calculated from a next instruction or instruction argument in a program sequence; reading from the memory a current instruction or instruction argument of the program; calculating a current redundancy code from the current instruction or instruction argument read from the memory; comparing the current redundancy code with a stored redundancy code stored with a previous instruction or instruction argument of the program; generating a fault indication if the current redundancy code does not match the stored redundancy code, wherein the redundancy code enables checking that both the instruction or instruction argument and the program sequence have not been modified; and storing in the memory an initialization instruction with a redundancy code which is a function of a first instruction of the program; and wherein the stored redundancy code further includes a code which is a function of another instruction that is a target of a conditional jump instruction in the program.