Підвищення стійкості шифрування інформації в оптико-електронних системах блочними шифрами на основі використання багаторівневих гніздових підстановочно-перестановочних мереж

Abstract

This article contains cipher transformation that consists of linear and nonlinear layers. The linear layer is constructed with the usage of nested substitution-permutation network. The network consists of three levels: the low level, the middle level and the high level. Each of the levels uses maximal distance codes. The increasing of number of active S-boxes for this transformation that are using this king of linear layer is proved. The variants of realization of the cipher transformation which uses substitution-permutation network for 8×8 and 16×16-bit S-boxes are considered. The variant of realization with the highest cryptography security is defined.