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On weakly APN functions and 4-bit S-Boxes (1102.3882v3)
Published 17 Feb 2011 in cs.CR and math.CO
Abstract: S-Boxes are important security components of block ciphers. We provide theoretical results on necessary or sufficient criteria for an (invertible) 4-bit S-Box to be weakly APN. Thanks to a classification of 4-bit invertible S-Boxes achieved independently by De Canni\'ere and Leander-Poschmann, we can strengthen our results with a computer-aided proof.