Reversing Florida State University’s Scalable Pseudo Random Number Generator (SPRNG)

Source abstract

In using a stream of pseudo-random numbers, they always generate in a set order given the seed. Using that seed, it becomes possible to generate the same period in reverse. by using two different streams to generate a single repeatable period with two different processors and a single seed, it becomes possible to generate random numbers in parallel without extra input. Additionally, "storing" numbers from a generator by operating the same generator in reverse provides easy storage without significant overhead. In this paper we took the generators used in SPRNG and evaluated how they could be reversed in practice whilst maintaining the current generation period.