Multi-block collisions in hash functions based on 3C and 3C+ enhancements of the Merkle-Damgård construction

Abstract

At the ACISP 2006 conference Praveen Gauravaram et al [2] proposed 3C and 3C+ constructions as enhancements of the Merkle-Damgård construction of cryptographic hash functions. They conjectured these constructions improved multi-block collision resistance of the hash functions. In this paper we show that the recently found collision attack on MD5 can be easily extended to the 3C and 3C+ constructions based on the MD5 compression function. In fact we show that if an algorithm satisfying some mild assumptions can find multi-block collisions for the Merkle-Damgård construction then it can be easily modified to find multi-block collisions for the 3C and 3C+ constructions based on the same compression function. © Springer-Verlag Berlin Heidelberg 2006.