A study on random bit generators with post-processing by shift registers and modulo-2 addition

Generation of random bit sequences with good statistical properties is proposed, where a simple post-processing by shift registers and modulo-2 addition is employed. The proposed method is based on modulo-2 addition of periodic and aperiodic binary sequences, where it is necessary to generate a balanced aperiodic binary sequence before modulo-2 adding to a periodic sequence. In this paper, we propose a simple method to obtain balanced aperiodic sequences from imbalanced ones. We discuss the statistical properties of sequences generated by the proposed generator theoretically and numerically including a well-known statistical test (FIPS140-2).