Security of permutation-based compression function lp231

Abstract

In this paper, we study security of a certain class of permutation-based compression functions. Denoted by lp231 in [10], they are 2n-to-n-bit compression functions using three calls to a single n-bit random permutation. We prove that lp231 is asymptotically preimage resistant up to 2(2n/3)/n query complexity and collision resistant up to 2(n/2)/n(1+epsilon) query complexity for any epsilon > 0. Based on a single permutation, lp231 provides both efficiency and almost optimal collision security. (C) 2014 Elsevier B.V. All rights reserved.