On the Impossibility of Highly-Efficient Blockcipher-Based Hash Functions

John Black; Martin Cochran; Thomas Shrimpton

Paper 2007/223

On the Impossibility of Highly-Efficient Blockcipher-Based Hash Functions

John Black, Martin Cochran, and Thomas Shrimpton

Abstract

Fix a small, non-empty set of blockcipher keys $K$ . We say a blockcipher-based hash function is highly-efficient if it makes exactly one blockcipher call for each message block hashed, and all blockcipher calls use a key from $K$ . Although a few highly-efficient constructions have been proposed, no one has been able to prove their security. In this paper we prove, in the ideal-cipher model, that it is impossible to construct a highly-efficient iterated blockcipher-based hash function that is provably secure. Our result implies, in particular, that the Tweakable Chain Hash (TCH) construction suggested by Liskov, Rivest, and Wagner is not correct under an instantiation suggested for this construction, nor can TCH be correctly instantiated by any other efficient means.

Note: This version fixes an error in the main proof of the paper published in Eurocrypt '05. That version incorrectly assumed that MD-strengthening does not affect the attack when more than one blockcipher key is used.

Metadata

Available format(s): PDF PS
Publication info: Published elsewhere. Previously appeared in the proceedings of Eurocrypt '05
Keywords: blockciphers hash functions
Contact author(s): cochranm @ colorado edu
History: 2007-06-09: received
Short URL: https://ia.cr/2007/223
License: CC BY

BibTeX

@misc{cryptoeprint:2007/223,
      author = {John Black and Martin Cochran and Thomas Shrimpton},
      title = {On the Impossibility of Highly-Efficient Blockcipher-Based Hash Functions},
      howpublished = {Cryptology {ePrint} Archive, Paper 2007/223},
      year = {2007},
      url = {https://eprint.iacr.org/2007/223}
}