Observations on the SIMON Block Cipher Family

Stefan Kölbl, Gregor Leander, Tyge Tiessen

Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


In this paper we analyse the general class of functions underlying 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.
Original languageEnglish
Title of host publicationAdvances in Cryptology – CRYPTO 2015 : Proceedings of the 35th Annual Cryptology Conference, Part 1
EditorsRosario Gennaro, Matthew Robshaw
Publication date2015
ISBN (Print)978-3-662-47988-9
ISBN (Electronic)978-3-662-47989-6
Publication statusPublished - 2015
Event35th International Cryptology Conference (CRYPTO 2015) - University of California, Santa Barbara, United States
Duration: 16 Aug 201520 Aug 2015
Conference number: 35


Conference35th International Cryptology Conference (CRYPTO 2015)
LocationUniversity of California
CountryUnited States
CitySanta Barbara
Internet address
SeriesLecture Notes in Computer Science


  • Differential cryptanalysis
  • Linear cryptanalysis
  • Block cipher
  • Boolean functions

Cite this

Kölbl, S., Leander, G., & Tiessen, T. (2015). Observations on the SIMON Block Cipher Family. In R. Gennaro, & M. Robshaw (Eds.), Advances in Cryptology – CRYPTO 2015: Proceedings of the 35th Annual Cryptology Conference, Part 1 (pp. 161-185). Springer. Lecture Notes in Computer Science, Vol.. 9215 https://doi.org/10.1007/978-3-662-47989-6_8