Cryptology ePrint Archive: Report 2009/034
On a Conditional Collision Attack on NaSHA-512
S. Markovski, A. Mileva, V. Dimitrova and D. Gligoroski
Abstract: A collision attack on NaSHA-512 was proposed by L. Ji et al. The
claimed complexity of the attack is $2^{192}$. The proposed attack
is realized by using a suitable differential pattern. In this note
we show that the correct result that can be inferred from their
differential pattern is in fact a conditional one. It can be
stated correctly as follows: A collision attack on NaSHA-512 of
complexity $k=1,2,\dots,2^{320}$ can be performed with an unknown
probability of success $p_k$, where $ 0\le p_1\le p_2\le
p_{2^{320}}\le 1$. Consequently, the attack proposed by L. Ji et
al. can be considered only as a direction how a possible collision
attack on NaSHA-512 could be realized. The birthday attack remains
the best possible attack on NaSHA-512.
Category / Keywords: Cryptografic hash function, NaSHA
Date: received 15 Jan 2009
Contact author: aleksandra mileva at ugd edu mk
Available format(s): PDF | BibTeX Citation
Version: 20090117:032444 (All versions of this report)
Short URL: ia.cr/2009/034
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