Investigating the Role of D Flip-Flop as a Synchronization Circuit for Enhancing Randomness and Stabilizing Bit Distribution in Ro-Based Rng on Fpga

Random number generators (RNGs) are crucial in applications requiring unpredictable sequences, including cryptography, simulations, and gaming. Among the different types of RNGs, ring oscillator (RO)-based RNGs have gained popularity due to their simplicity, and suitability for FPGA implementation. Previous research by Wold et al. has suggested that connecting directly a D flip-flop (D-FF) to the RO circuit enhances randomness. However, the precise factors contributing to the improved randomness through the connection of the D-FF remain unclear. Then, we hypothesize that the D-FF acts as a synchronization circuit, enhances randomness. To verify this hypothesis, we design and implement RO-based RNG circuits with and without a D-FF directly connected to the RO circuit on an FPGA platform. By analyzing and comparing the bit distribution of the generated number sequences, we investigate the impact of the D-FF on the stability of the generated numbers. The results confirm that incorporating a D-FF into the RO-based RNG circuit stabilizes the random number sequence, leading to the conclusion that the D-FF plays a synchronization role in these circuits.