Cryptology ePrint Archive: Report 2012/141

Bicliques for permutations: collision and preimage attacks in stronger settings

Dmitry Khovratovich

Abstract: We extend and improve biclique attacks, which were recently introduced for the cryptanalysis of block ciphers and hash functions. While previous attacks required a primitive to have a key or a message schedule, we show how to mount attacks on the primitives with these parameters fixed, i.e. on permutations. We introduce the concept of sliced bicliques, which is a translation of regular bicliques to the framework with permutations.

The new framework allows to convert preimage attacks into collision attacks and derive the first collision attacks on the reduced SHA-3 finalist Skein in the hash function setting up to 11 rounds. We also demonstrate new preimage attacks on the reduced Skein and the output transformation of the reduced Grøstl. Finally, the sophisticated technique of message compensation gets a simple explanation with bicliques.

Category / Keywords: Skein, SHA-3, hash function, collision attack, preimage attack, biclique, permutation, Gr{\o}stl

Publication Info: submitted

Date: received 15 Mar 2012, last revised 1 Jun 2012

Contact author: khovratovich at gmail com

Available format(s): PDF | BibTeX Citation

Note: Description of the method completely revised.

Version: 20120601:173222 (All versions of this report)

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