<p>This article deals with the problem of generating a non-linear reflection block (S-box), which is one of the important parts of the block cypher standards developed in modern cryptography. It is being emphasized that reliable cryptographic encryption algorithms are needed in order to ensure the confidentiality of data exchanged by users. The article proposes a new approach to creating a secure S-box for symmetric encryption algorithms by choosing adjacency matrix parameters. The results from this algorithm yielded values that are close to recommended indicators for high overall non-linearity and solid avalanche efficiency. 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.</p>