Probability distributions for the Linux entropy estimator

We propose a mathematical model of the entropy estimator in the Linux random number generator. First, we construct a probability model for random event times in entropy sources, and then precisely derive probability distributions for the first, second, and third time differences. Second, we obtain the probability distribution for the minimum of absolute values of these differences, which is used for the estimated entropy in the Linux system. Moreover, we provide several simulations that display the accuracy of our results for various parameters.