PSEUDO RANDOM BIT STREAM GENERATOR AND CIPHERING COMMUNICATION METHOD USING THE SAME

摘要

PROBLEM TO BE SOLVED: To obtain a pseudo random bit generator with improved security and a simple circuit configuration of a pseudo random bit generator employing a plurality of FSRs by providing a means that feeds back an output of an exclusive OR means to a plurality of feedback shift registers(FSRs). ;SOLUTION: A circuit shown in dashed lines is inputted with an exclusive OR so that a seed (secret key) is dynamically changed in a basic pseudo random bit sequence generator. This input is generated by a register H of a nonlinear auxiliary circuit. The register H is added to the basic pseudo random bit stream generator where contents of each FSR are dynamically changed for each circuit operation to configure a dynamic basic pseudo random bit sequence generator. At first, the Seed is inputted to each FSR and an auxiliary circuit and data are shifted one by one bit sequentially while synchronizing a shift clock with a communication speed. The register H sends data to each FSR to change the Seed dynamically. Then exclusive OR processing is applied to an output from each FSR.;COPYRIGHT: (C)1998,JPO