A Preimage Attack for 52-Step HAS-160

摘要

In this paper, we propose preimage attacks on the hash function HAS-160, which is standardized in Korea. We propose two approaches to generate a preimage of step-reduced HAS-160 faster than a brute force attack, which costs 2~(160). The first approach is a simple application of previously known techniques, which are so-called splice-and-cut ant partial-matching techniques. This approach generates a pseudo-preimage of 48 steps of HAS-160 with a complexity of 2~(128) and a preimage with a complexity of 2~(145). In the second approach, we consider a variant of so-called local-collision technique. This approach generates a pseudo-preimage of 52 steps of HAS-160 with a complexity of 2~(144) and a preimage with a complexity of 2~(153). To the best of our knowledge, this is the first paper that analyzes the preimage resistance of HAS-160.