Design of a High Jitter Harmonic Injected Ring Oscillator for Entropy Sources

in the field of modern cryptography and-information security, the generation of random numbers is crucial, with the quality of the entropy source being paramount. This study explores the design of Ring Oscillator (RO)-based entropy sources, noted for their high manufacturability and ease of integration. However, the jitter produced by naive ROs is insufficient for high-quality entropy. We propose a design that significantly enhances jitter performance through the introduction of a harmonic injection path. This approach maintains high synthesizability while incurring only modest increases in area and power consumption. Experimental results demonstrate that the modified RO,fa bricated using a 180 nm process, elevated the average min-entropy from $0.058 / \mathrm{bit}$ to 0.351/bit, offering new insights and substantial support for the development of high-quality random number generators.