Analytical Substantiation of the Use of GFSR-generators in the Tasks of Cryptography

The analysis of problems associated with theoretical and practical substantiation of principles of construction of combined pseudo-random sequence generators based on the generalized feedback shift registers was conducted. It is shown that one of the promising ways to build combined generators of pseudo-random sequences is a compromise combination of the principles used as the basis for the synthesis of GFSR-generators with non-linear multiplicative filters with their own finite memory. The use of such an approach is justified by the fact that under a large period of sequences formed by the GFSR-generators, the number of generator polynomials defining the type of feedback is relatively small, which simplifies the task for cryptanalysts. Introduction of a non-linearity is an economical way to solve the problem of increasing the cryptographic protection and can be used in the design of modern information security systems and development of new ciphers