CryptoDB
Column Parity Mixers
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| Abstract: | We present column parity mixers (CPM), a generalization of the Θ mixing layer that is used in Keccak. Thanks to our description using matrix arithmetic, we can easily derive algebraic, diffusion, and mask propagation properties, leading to a surprising distinction between two types of CPMs. We compare CPMs to other popular types of mixing layers and argue that CPMs can be more efficient. While Keccak has a bit-oriented structure, we make the case that CPMs are also suitable for nibble- or byte-oriented designs. We outline a general substitution-permutation-network-based design strategy using a CPM, for which we show how one can attain strong bounds for differential and linear trails. We apply this strategy concretely to design a 256-bit permutation with an efficient inverse and strong trail bounds. Our permutation design uses a number of ideas that are of independent interest and allows a fast bitsliced implementation that compares quite well with other established ciphers and permutations. |
BibTeX
@article{tosc-2018-28395,
title={Column Parity Mixers},
journal={IACR Trans. Symmetric Cryptol.},
publisher={Ruhr-Universität Bochum},
volume={2018, Issue 1},
pages={126-159},
url={https://tosc.iacr.org/index.php/ToSC/article/view/847},
doi={10.13154/tosc.v2018.i1.126-159},
author={Ko Stoffelen and Joan Daemen},
year=2018
}