Influence of S-Boxes to the resistance of GOST algorithm against linear cryptanalysis
Liudmila K. Babenko, Evgeniya Ishchukova · 2013
This work is devoted to finding the influence of S-Boxes to resistance of GOST 28147-89 algorithm (GOST) against linear cryptanalysis. The universal algorithm for searching particular layouts of S-Boxes, which are vulnerable to linear cryptanalysis is presented. The possibility of building of efficient linear statistical expressions for simplified GOST with weak S-Boxes has been shown. This research is aimed to ensuring that certain arbitrary S-Box layouts are not weak when they are not fixed. Applicability of the presented method was tested by analyzing S-Boxes used in GOST. Application of the designed method made it possible to discover a number of weak S-Boxes, which make the overall cryptographic strength of GOST much lower.