Paper 2012/440
New Preimage Attacks Against Reduced SHA-1
Simon Knellwolf and Dmitry Khovratovich
Abstract
This paper shows preimage attacks against reduced SHA-1 up to 57 steps. The best previous attack has been presented at CRYPTO 2009 and was for 48 steps finding a two-block preimage with incorrect padding at the cost of 2159.3 evaluations of the compression function. For the same variant our attacks find a one-block preimage at 2150.6 and a correctly padded two-block preimage at 2151.1 evaluations of the compression function. The improved results come out of a differential view on the meet-in-the-middle technique originally developed by Aoki and Sasaki. The new framework closely relates meet-in-the-middle attacks to differential cryptanalysis which turns out to be particularly useful for hash functions with linear message expansion and weak diffusion properties.
Metadata
- Available format(s)
-
PDF
- Category
- Secret-key cryptography
- Publication info
- Published elsewhere. A short version of this paper appears at Crypto 2012.
- Keywords
- cryptanalysishash functionsSHA-1preimage attackmeet-in-the-middle
- Contact author(s)
- simon knellwolf @ fhnw ch
- History
- 2012-08-05: received
- Short URL
- https://ia.cr/2012/440
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2012/440,
author = {Simon Knellwolf and Dmitry Khovratovich},
title = {New Preimage Attacks Against Reduced {SHA}-1},
howpublished = {Cryptology {ePrint} Archive, Paper 2012/440},
year = {2012},
url = {https://eprint.iacr.org/2012/440}
}
