Transactions on Symmetric Cryptology, Volume 2025
Generalizations of ChiChi: Families of Low-Latency Permutations in Any Even Dimension
Samuele Andreoli
University of Bergen, Bergen, Norway
Gregor Leander
Ruhr University Bochum, Bochum, Germany
Enrico Piccione
University of Bergen, Bergen, Norway
Lukas Stennes
cryptosolutions GmbH, Essen, Germany
Keywords: Non-linear layer, Boolean functions, Chi, ChiChi
Abstract
At Eurocrypt 2025, Belkheyar et al. introduced a new non-linear layer called ChiChi, built from Daemen's chi function but yielding a permutation in even dimension divisible by four. In this work, we generalize their construction in multiple ways, prove their open conjecture regarding the algebraic degree of the inverse of ChiChi, and investigate its properties against key-recovery attacks.
Publication
Transactions on Symmetric Cryptology, Volume 2025, Issue 3
PaperArtifact
Artifact number
fse/2026/a8
Artifact published
June 22, 2026
Badge
IACR FSE Artifacts Functional
License
This work is licensed under the MIT License.
Note that license information is supplied by the authors and has not been confirmed by the IACR.
BibTeX How to cite
Samuele Andreoli, Gregor Leander, Enrico Piccione, and Lukas Stennes. (2025). Generalizations of ChiChi: Families of Low-Latency Permutations in Any Even Dimension. Transactions on Symmetric Cryptology, 2025(3), 800-826. https://doi.org/10.46586/tosc.v2025.i3.800-826. Artifact available at https://artifacts.iacr.org/fse/2026/a8