Fast algorithm of generation of substations of multiple-alphabetic replacement

Abstract

An actual model of the cyber-security offender for automated control systems of the technological processes (APS TP), using global networks as a transport was proposed in this article. Basing on the threats to confidentiality and integrity of information, an analysis of methods of counteracting network manipulation and basic methods were made, that methods ensured the conversion of pseudo-random sequences into substitution sequences of the appropriate degree for the implementation of the multi-alphabetical replacement cipher. Within the framework of the work, a fast algorithm for realizing the multi-alphabetical replacement cipher with the use of the cipher sequence from the block cipher in the OFB mode was proposed, the correctness of the corresponding procedure was proved, and the possibility of forming any substitution from the symmetric permutation group .. The simulation modeling of the algorithm was performed, it allowed to confirm the necessary of the statistical qualities of the matrix of the cipher transition probabilities, which will ensure a high level of encryption and imitation resistance of commands and service information, circulating in the mentioned APS TP.