[Resource Topic] 2012/440: New Preimage Attacks Against Reduced SHA-1

Welcome to the resource topic for 2012/440

Title:
New Preimage Attacks Against Reduced SHA-1

Authors: Simon Knellwolf, 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.

ePrint: https://eprint.iacr.org/2012/440

Talk: https://www.youtube.com/watch?v=zkU2VKxdl9E

Slides: https://iacr.org/cryptodb/archive/2012/CRYPTO/presentation/6-3-Knellwolf.pdf

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