Modeling and simulation of oscillator-based random number generators

The design of integrated-circuit random number generators is receiving increased attention for the purpose of secure communications. Many high-speed cryptographic circuit-systems require a nondeterministic source of random bits. The security of these systems depends on the predictability or level of randomness of the generated bit stream. One popular method of generating random bits is to use the random frequency variations of free-running ring oscillators. This paper presents a behavioral model for the simulation of oscillator-based random number generators. The method of random number generation using oscillators is described and important design issues are stated. A model is developed and simulation results are presented for the purpose of addressing these design issues.