Further Improving Differential-Linear Attacks: Applications to Chaskey and Serpent

Marek Broll; Federico Canale; Nicolas David; Antonio Florez-Gutierrez; Gregor Leander; María Naya-Plasencia; Yosuke Todo

Paper 2021/820

Further Improving Differential-Linear Attacks: Applications to Chaskey and Serpent

Marek Broll, Federico Canale, Nicolas David, Antonio Florez-Gutierrez, Gregor Leander, María Naya-Plasencia, and Yosuke Todo

Abstract

Differential-linear attacks are a cryptanalysis family that has recently benefited from various technical improvements, mainly in the context of ARX constructions. In this paper we push further this refinement, proposing several new improvements. In particular, we develop a better understanding of the related correlations, improve upon the statistics by using the LLR, and finally use ideas from conditional differentials for finding many right pairs. We illustrate the usefulness of these ideas by presenting the first 7.5-round attack on Chaskey. Finally, we present a new competitive attack on 12 rounds of Serpent, and as such the first cryptanalytic progress on Serpent in 10 years.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: cryptanalysis differential-linear attack partitions LLR Chaskey Serpent conditional-differential
Contact author(s): marek broll @ rub de
federico canale @ rub de
nicolas david @ inria fr
antonio florez-gutierrez @ inria fr
gregor leander @ rub de
maria naya_plasencia @ inria fr
yosuke todo xt @ hco ntt co jp
History: 2021-06-16: received
Short URL: https://ia.cr/2021/820
License: CC BY

BibTeX

@misc{cryptoeprint:2021/820,
      author = {Marek Broll and Federico Canale and Nicolas David and Antonio Florez-Gutierrez and Gregor Leander and María Naya-Plasencia and Yosuke Todo},
      title = {Further Improving Differential-Linear Attacks: Applications to Chaskey and Serpent},
      howpublished = {Cryptology ePrint Archive, Paper 2021/820},
      year = {2021},
      note = {\url{https://eprint.iacr.org/2021/820}},
      url = {https://eprint.iacr.org/2021/820}
}