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Message Recovery and Pseudo-Preimage Attacks on the Compression Function of Hamsi-256

Authors:
Çagdas Çalik
Meltem Sönmez Turan
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URL: http://eprint.iacr.org/2010/057
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Abstract: Hamsi is one of the second round candidates of the SHA-3 competition. In this study, we present non-random differential properties for the compression function of the hash function Hamsi-256. Based on these properties, we first demonstrate a distinguishing attack that requires a few evaluations of the compression function and extend the distinguisher to 5 rounds with complexity $2^{83}$. Then, we present a message recovery attack with complexity of $2^{10.48}$ compression function evaluations. Also, we present a pseudo-preimage attack for the compression function with complexity $2^{254.25}$. The pseudo-preimage attack on the compression function is easily converted to a pseudo second preimage attack on Hamsi-256 hash function with the same complexity.
BibTeX
@misc{eprint-2010-22958,
  title={Message Recovery and Pseudo-Preimage Attacks on the Compression Function of Hamsi-256},
  booktitle={IACR Eprint archive},
  keywords={secret-key cryptography / Hash functions, SHA-3 competition, cryptanalysis, preimage attacks},
  url={http://eprint.iacr.org/2010/057},
  note={ meltemsturan@gmail.com 14655 received 2 Feb 2010, last revised 15 Feb 2010},
  author={Çagdas Çalik and Meltem Sönmez Turan},
  year=2010
}