Cryptology ePrint Archive: Report 2015/145
Observations on the SIMON block cipher family
Stefan Kölbl and Gregor Leander and Tyge Tiessen
Abstract: In this paper we analyse the general class of functions underly-
ing the Simon block cipher. In particular, we derive efficiently computable and easily implementable expressions for the exact differential and linear behaviour of Simon-like round functions.
Following up on this, we use those expressions for a computer aided
approach based on SAT/SMT solvers to find both optimal differential
and linear characteristics for Simon. Furthermore, we are able to find all characteristics contributing to the probability of a differential for Simon32 and give better estimates for the probability for other variants.
Finally, we investigate a large set of Simon variants using different rotation constants with respect to their resistance against differential and linear cryptanalysis. Interestingly, the default parameters seem to be not always optimal.
Category / Keywords: SIMON, block cipher, differential cryptanalysis, linear cryptanalysis, boolean functions
Original Publication (with minor differences): IACR-CRYPTO-2015
Date: received 20 Feb 2015, last revised 3 Jul 2015
Contact author: stek at dtu dk
Available format(s): PDF | BibTeX Citation
Note: Updated to the revised version of CRYPTO and supplementary tutorial.
Version: 20150703:092944 (All versions of this report)
Short URL: ia.cr/2015/145
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