Fast Implementation of LSH With SIMD

Abstract

In this paper, we propose a method of efficient software implementation for the cryptographic hash function LSH with single instruction multiple data (SIMD). The method is based on word-wise permutations of LSH. Using the modified functions Step(j)' = P o Step(j) oP(-1) and MsgExp' instead of the original step function Step(j) and message expansion function MsgExp, where P is a permutation and P-1 is the inverse permutation of P, we show that the number of the SIMD instructions for implementing LSH is reduced. For efficient implementation of LSH in other environments (e.g., MIMD), various types of word permutations are listed.