The Boomerang Attacks on BLAKE and BLAKE2

Yonglin Hao

Paper 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.

Note: My first study on Hash Functions

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Published elsewhere. Minor revision. Inscrypt 2014
Keywords: Cryptanalysis Boomerang BLAKE BLAKE2 Message Modification Differential Characteristics
Contact author(s): haoyl14 @ mails tsinghua edu cn
History: 2014-12-26: received
Short URL: https://ia.cr/2014/1012
License: CC BY

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}
}