A Simple Pseudorandom Bit Generator using Frequency Controlled Digital Chaos

A novel kind of chaos, digital chaos is proposed, and an extremely simple circuit to generate frequency controlled digital chaos using two XOR gates driven by three square signals with mismatched frequencies and duty cycles is designed and implemented in FPGA, with the basic principle that the XOR being a difference circuit, amplifies the mismatches, leading to chaos generation. The presence of chaos is ascertained using Lyapunov Exponent and the effect of driving signal frequency on the chaotic nature is studied. The generated chaotic bit sequence is then tested for randomness using standard tests from the NIST Test Suite. It is found that the generated digital chaotic bit sequence is indeed random, proving capability of the proposed circuit as a pseudo random bit generator for computing and communication applications