On Measuring Security Bounds of Some Ciphers Using Mixed Integer Linear Programming (MILP) Approach

Türesin, Can
Block ciphers are one of the symmetric key encryption algorithms that are used in many devices. Its increasing popularity has led to the emergence of new cryptanalysis methods. Therefore, measuring block cipher's security bounds is one main indispensable need for its designers. Two of the most effective attacks on block ciphers are differential and linear cryptanalysis and these attacks' efficiencies are bonded with a number of active S-boxes of the cipher after a certain number of rounds. Consequently, measuring the number of active S-boxes is one of the techniques to measure the security bounds. There are various methods to calculate this number, both mathematically, and automatically. This thesis focuses on computing the minimum number of active S-boxes automatically, more specifically, using an optimization method called Mixed Integer Linear Programming, a method that achieved noticeable success across both the industrial and academic world. In this thesis, a summary of the studies in the literature on how to calculate the minimum number of active S-boxes with MILP will be given, the author's own ideas on this subject will also be shared, and the performance results of recent works and author's ideas will be compared.


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Citation Formats
C. Türesin, “On Measuring Security Bounds of Some Ciphers Using Mixed Integer Linear Programming (MILP) Approach,” M.S. - Master of Science, Middle East Technical University, 2021.