ACAC Seminar Abstract

ACAC Seminar Abstract

ACAC Seminars

ACAC Seminar Abstract

Extending FORK-256 Attack to the Full Hash Function

Speaker: Krystian Matusiewicz
Date, Time: Fri, 07 Dec 2007 14:00

FORK-256 is a dedicated hash function proposed by Hong at al. and presented at FSE 2006. Possibly due to some unorthodox design choices, it received considerable attention from cryptanalysts and an attack on the full compression function of FORK-256 was presented during FSE 2007. That attack required choosing an IV and did not work for the original IV proposed in the specification. In this talk we present an extension of the FSE'07 attack that deals with that problem. By reducing the number of initial values that have to be manipulated from 4 to 3, it allows for finding near-collisions and collisions for FORK-256 with any predefined IV, in particular the original one given in the specification. We also discuss some possible further improvements and mention both a new, patched version of FORK-256 and a recent result by Saarinen that allows for finding collisions in both old and new FORK-256.

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