Paper 2014/1012 Original: eprint.iacr.org/2014/1012 ↗

The Boomerang Attacks on BLAKE and BLAKE2

Yonglin Hao
Abstract

n this paper, we study the security margins of hash functions BLAKE and BLAKE2 against the boomerang attack. We launch boomerang attacks on all four members of BLAKE and BLAKE2, and compare their complexities. We propose 8.5-round boomerang attacks on both BLAKE-512 and BLAKE2b with complexities $2^{464}$ and $2^{474}$ respectively. We also propose 8-round attacks on BLAKE-256 with complexity $2^{198}$ and 7.5-round attacks on BLAKE2s with complexity $2^{184}$. We verify the correctness of our analysis by giving practical 6.5-round Type I boomerang quartets for each member of BLAKE and BLAKE2. According to our analysis, some tweaks introduced by BLAKE2 have increased its resistance against boomerang attacks to a certain extent. But on the whole, BLAKE still has higher a secure margin than BLAKE2.

Metadata
Available format(s)
PDF
Category
Secret-key cryptography
Publication info
Preprint.
History
2014-12-26: last updated
2014-12-26: published
Short URL
https://ia.cr/2014/1012
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2014/1012,
      author = {Yonglin Hao},
      title = {The Boomerang Attacks on BLAKE and BLAKE2},
      howpublished = {Cryptology {ePrint} Archive, Paper 2014/1012},
      year = {2014},
      url = {https://eprint.iacr.org/2014/1012}
}
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