Patent ID: 7092523

Claim:
A method of an executable program of a cryptographic processor masking a conditional jump operation in said cryptographic processor, said cryptographic processor being programmed such that said executable program executes a sequence of instructions, wherein the conditional jump is determined by said executable program evaluating a distinguishing value V against a reference value and wherein the reference value is bounded by an upper limit Vmax and a lower limit Vmin, the method comprising the steps of: (a) determining a location of said conditional jump in said executable program; and (b) inserting processor instructions at said location to direct execution of said program to one of two branches, said processor instructions computing a target address in said processor instructions, the target address being derived from said distinguishing value and a base address constituted by a random number, wherein for each evaluation of said distinguishing value against said reference value one of said branches is selected and a random number of processor instructions are executed within said branch for directing program flow to said one of two branches.