THE ALGORITHM FOR COMPUTING THE S-BOXES WITH IMPROVED STRICT AVALANCHE CRITERION AND HIGH NON-LINEARITY BY SELECTING DIRECTED GRAPH PARAMETERS

Abstract

This article deals with the problem of generating a non-linear refl ection block (S-box), which is one of the important parts of the block cipher stan-dards developed in modern cryptography. It is being emphasized that reliable cryptographic encryption al-gorithms are needed in order to ensure the confi denti-ality of data exchanged by users. The article proposes a new approach to creating a secure S-box for sym-metric encryption algorithms by choosing adjacency matrix parameters. The results from this algorithm yielded values that are close to recommended indica-tors for high overall non-linearity and solid avalanche effi ciency. These values are: N(f) = 112 в S1{8 x 8}, N(S) = 112, deg(f) = 7, AI = 2, SACaver = 0,5 и S2{8 x 8}, N(S) = 112, deg(f) = 7, AI = 2, SACaver = 0.5. It is shown that this method can generate strong S-box values for block-symmetric encryption algorithms