IACR News item: 18 July 2015
Anne Canteaut, Sébastien Duval, Gaëtan Leurent
ePrint Reportbits, having both good cryptographic properties and a low implementation
cost. Such S-Boxes are suitable building-blocks in many lightweight
block ciphers since they may achieve a better security level than
designs based directly on smaller S-Boxes. We focus on S-Boxes
corresponding to three rounds of a balanced Feistel and of a balanced
MISTY structure, and generalize the recent results by Li and Wang on the
best differential uniformity and linearity offered by such a
construction. Most notably, we prove that Feistel networks supersede
MISTY networks for the construction of 8-bit permutations. Based on
these results, we also provide a particular instantiation of an 8-bit
permutation with better properties than the S-Boxes used in several
ciphers, including Robin, Fantomas or CRYPTON.
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