Design of Tree Filter Algorithm for Random Number Generator in Crypto Module

Abstract

For a hardware random number generator (RNG) in a crypto module, it is important that the RNG hardware offers an output bit stream that is always unbiased. J. H., et al. proposed a combination of the hardware component and a software filter algorithm. However, even though the hardware generating processor generates an output bit stream quickly, if the software filter algorithm is inefficient, the RNG becomes time consuming, thereby restricting the conditions when an RNG can be applied. Accordingly, this paper proposes an effective method of software filtering for an RNG processor in a crypto module. To consistently guarantee the randomness of the output sequence from a RNG, the origin must be stabilized, regardless of any change in circumstances. Therefore, a tree model is proposed to apply the filter algorithm, making it less time consuming than J. H.’s conventional filter algorithm scheme.