Paper 2009/184
Cryptanalysis of Dynamic SHA(2)
Jean-Philippe Aumasson, Orr Dunkelman, Sebastiaan Indesteege, and Bart Preneel
Abstract
In this paper, we analyze the hash functions Dynamic SHA and Dynamic SHA2, which have been selected as first round candidates in the NIST hash function competition. These hash functions rely heavily on data-dependent rotations, similar to certain block ciphers, e.g., RC5. Our analysis suggests that in the case of hash functions, where the attacker has more control over the rotations, this approach is less favorable than in block ciphers. We present practical, or close to practical, collision attacks on both Dynamic SHA and Dynamic SHA2. Moreover, we present a preimage attack on Dynamic SHA that is faster than exhaustive search.
Note: Typo fixed in one equation.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. Accepted to SAC 2009
- Keywords
- hash functionspreimagecollisionSHA-3
- Contact author(s)
- jeanphilippe aumasson @ gmail com
- History
- 2009-08-27: last of 5 revisions
- 2009-05-02: received
- See all versions
- Short URL
- https://ia.cr/2009/184
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2009/184,
author = {Jean-Philippe Aumasson and Orr Dunkelman and Sebastiaan Indesteege and Bart Preneel},
title = {Cryptanalysis of Dynamic {SHA}(2)},
howpublished = {Cryptology {ePrint} Archive, Paper 2009/184},
year = {2009},
url = {https://eprint.iacr.org/2009/184}
}
