Paper 2023/725 Original: eprint.iacr.org/2023/725 ↗
On Perfect Linear Approximations and Differentials over Two-Round SPNs
Abstract
Recent constructions of (tweakable) block ciphers with an embedded cryptographic backdoor relied on the existence of probability-one differentials or perfect (non-)linear approximations over a reduced-round version of the primitive. In this work, we study how the existence of probability-one differentials or perfect linear approximations over two rounds of a substitution-permutation network can be avoided by design. More precisely, we develop criteria on the s-box and the linear layer that guarantee the absence of probability-one differentials for all keys. We further present an algorithm that allows to efficiently exclude the existence of keys for which there exists a perfect linear approximation.
Metadata
- Available format(s)
PDF- Category
- Secret-key cryptography
- Publication info
- Preprint.
- History
- 2023-05-19: last updated
- 2023-05-19: published
- Short URL
- https://ia.cr/2023/725
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2023/725,
author = {Christof Beierle and Patrick Felke and Gregor Leander and Patrick Neumann and Lukas Stennes},
title = {On Perfect Linear Approximations and Differentials over Two-Round SPNs},
howpublished = {Cryptology {ePrint} Archive, Paper 2023/725},
year = {2023},
url = {https://eprint.iacr.org/2023/725}
}