Preimage Attacks on 3, 4, and 5-Pass HAVAL

This paper proposes preimage attacks on hash function HAVAL whose output length is 256 bits. This paper has three main contributions; a preimage attack on 3-pass HAVAL at the complexity of 2, a preimage attack on 4-pass HAVAL at the complexity of 2, and a preimage attack on 5-pass HAVAL reduced to 151 steps at the complexity of 2. Moreover, we optimize the computational order for brute-force attack on full 5-pass HAVAL and its complexity is 2. As far as we know, the proposed attack on 3-pass HAVAL is the best attack and there is no preimage attack so far on 4-pass and 5-pass HAVAL. Note that the complexity of the previous best attack on 3-pass HAVAL is 2. Technically, our attacks find pseudo-preimages of HAVAL by combining the meet-in-the-middle and local-collision approaches, then convert pseudopreimages to a preimage by using a generic algorithm. keywords: HAVAL, splice-and-cut, meet-in-the-middle, local collision, hash function, one-way, preimage