Multicollisions and graph-based hash functions

Abstract

In this paper, we present some generalisations of previous multicollision finding methods and apply these against a new type of tree-based hash functions. We also show that the very general class of hash functions first presented by Nandi and Stinson can be understood as graph-based hash functions and a graph theoretical approach can be utilised in studying their properties. Previously, an efficient multicollision attack has been found against the basic iterated hash function construction. This method has been applied to the generalised iterated hash functions and binary tree-based hash functions. We show that similar methods can be utilised also against t-ary tree-based hash functions, simplify some definitions and conjecture a similar result for multicollisions against graph-based hash functions. © 2012 Springer-Verlag.