A note on a recent attack against SPEEDY-7-192

Christina Boura; Patrick Derbez; Baptiste Germon; Rachelle Heim Boissier; María Naya-Plasencia

Paper 2025/1265

A note on a recent attack against SPEEDY-7-192

Christina Boura, IRIF, Université Paris Cité, France

Patrick Derbez, Univ Rennes, Inria, CNRS, IRISA, France

Baptiste Germon, Univ Rennes, Inria, CNRS, IRISA, France

Rachelle Heim Boissier, UCLouvain, ICTEAM/ELEN/Crypto Group, Belgium

María Naya-Plasencia, Inria, Paris, France

Abstract

Recently, two independent differential attacks on SPEEDY-7-192 were proposed by Boura et al. and by Beyne and Neyt. Both works present, for the first time, a valid differential attack on SPEEDY-7-192 with time complexities of $2^{186.36}$ and $2^{185}$ respectively. In this note, by extending the search space for 1-round trails, we propose a new differential attack on SPEEDY-7-192 with both data and time complexity of $2^{174.80}$. This improves upon both previous attacks by more than a factor of $2^{10}$.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint.
Keywords: differential cryptanalysis SPEEDY quasidifferentials
Contact author(s): christina boura @ irif fr
patrick derbez @ inria fr
baptiste germon @ inria fr
rachelle heim @ uclouvain be
maria naya-plasencia @ inria fr
History: 2025-07-11: approved; 2025-07-09: received; See all versions
Short URL: https://ia.cr/2025/1265
License: CC BY-SA

BibTeX

@misc{cryptoeprint:2025/1265,
      author = {Christina Boura and Patrick Derbez and Baptiste Germon and Rachelle Heim Boissier and María Naya-Plasencia},
      title = {A note on a recent attack against {SPEEDY}-7-192},
      howpublished = {Cryptology {ePrint} Archive, Paper 2025/1265},
      year = {2025},
      url = {https://eprint.iacr.org/2025/1265}
}