Bit permutation instructions for accelerating software cryptography

Permutation is widely used in cryprographic algorithms. However, it is not well-supported in existing instruction sets. In this paper, two instructions, PPERM3R and GRP, are proposed for efficient software implementation of arbitrary permutations. The PPERM3R instruction can be used for dynamically specified permutations; the GRP instruction can be used to do arbitrary n-bit permutations with up to lg(n) instructions. In addition, a systematic method for determining the instruction sequence for performing an arbitrary permutation is described.