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Paper: Improved Cryptanalysis of APOP-MD4 and NMAC-MD4 using New Differential Paths

Authors:
Donghoon Chang
Jaechul Sung
Seokhie Hong
Sangjin Lee
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URL: http://eprint.iacr.org/2008/048
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Abstract: In case of security analysis of hash functions, finding a good collision-inducing differential paths has been only focused on. However, it is not clear how differential paths of a hash function influence the securities of schemes based on the hash function. In this paper, we show that any differential path of a hash function can influence the securities of schemes based on the hash function. We explain this fact with the MD4 hash function. We first show that APOP-MD4 with a nonce of fixed length can be analyzed efficiently with a new differential path. Then we improve the result of the key-recovery attack on NMAC-MD4 described by Fouque {\em et al.} \cite{FoLeNg07} by combining new differential paths. Our results mean that good hash functions should have the following property : \textit{It is computationally infeasible to find differential a path of hash functions with a high probability}.
BibTeX
@misc{eprint-2008-17725,
  title={Improved Cryptanalysis of APOP-MD4 and NMAC-MD4 using New Differential Paths},
  booktitle={IACR Eprint archive},
  keywords={secret-key cryptography / MD4, Differential Path, APOP, NMAC.},
  url={http://eprint.iacr.org/2008/048},
  note={ pointchang@gmail.com 13908 received 29 Jan 2008},
  author={Donghoon Chang and Jaechul Sung and Seokhie Hong and Sangjin Lee},
  year=2008
}