A Chaos Based Pseudo-Random Bit Generator Using Multiple Digits Comparison

Abstract

This work presents a simple method of designing pseudo-random bit generator by generating multiple bits per iteration from the decimal part of a chaotic map. This is done by extracting the decimal part of the state in each iteration and comparing each digit separately to a threshold value. This way, more than one bits can be generated in each iteration, in contrast to most well-known generators based on discrete-time chaotic maps, which generate only one bit. The method is tested on multiple maps and it is seen that for most, around 8 digits can be extracted each time, so that the final bitstream passes all NIST tests. The generated PRBG is then studied through a simple image encryption application, by combining shuffling and the XOR operation.