A heuristic for finding compatible differential paths with application to HAS-160

Aleksandar Kircanski; Riham AlTawy; Amr M.  Youssef

Paper 2013/359

A heuristic for finding compatible differential paths with application to HAS-160

Aleksandar Kircanski, Riham AlTawy, and Amr M. Youssef

Abstract

The question of compatibility of differential paths plays a central role in second order collision attacks on hash functions. In this context, attacks typically proceed by starting from the middle and constructing the middle-steps quartet in which the two paths are enforced on the respec- tive faces of the quartet structure. Finding paths that can fit in such a quartet structure has been a major challenge and the currently known compatible paths extend over a suboptimal number of steps for hash functions such as SHA-2 and HAS-160. In this paper, we investigate a heuristic that searches for compatible differential paths. The application of the heuristic in case of HAS-160 yields a practical second order collision over all of the function steps, which is the first practical result that covers all of the HAS-160 steps. An example of a colliding quartet is provided

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Published elsewhere. Unknown where it was published
Contact author(s): akircanski @ gmail com
History: 2013-06-10: received
Short URL: https://ia.cr/2013/359
License: CC BY

BibTeX

@misc{cryptoeprint:2013/359,
      author = {Aleksandar Kircanski and Riham AlTawy and Amr M.  Youssef},
      title = {A heuristic for finding compatible differential paths with application to {HAS}-160},
      howpublished = {Cryptology {ePrint} Archive, Paper 2013/359},
      year = {2013},
      url = {https://eprint.iacr.org/2013/359}
}