Cryptanalysis of the Full HAVAL with 4 and 5 Passes

Abstract

HAVAL is a cryptographic hash function with variable digest size proposed by Zheng, Pieprzyk and Seberry in 1992, It has three variants, 3-, 4-, and 5-pass HAVAL, Previous results on HAVAL suggested only practical collision attacks for 3-pass HAVAL, In this paper, we present collision attacks for 4 and 5 pass HAVAL, For 4-pass HAVAL, we describe two practical attacks for finding 2-block collisions, one with 243 computations and the other with 236 computations. In addition, we show that collisions for 5-pass HAVAL can be found with about 2123 computations, which is the first attack more efficient than the birthday attack.