Dmytryshyn O. Methods and means of the block ciphers for increased security based on the arithmetic operations after the modulo.

A research object is the process of cryptographic security of information in computer systems; the aim of work is to improve information security in computer systems by developing methods and tools for block cipher cryptographic strength increased on the basis of arithmetic operations after the modulo; used methods of number theory, methods of cryptology, the methods of mathematical statistics,methods of automata theory; theoretical results - the method of symmetric block cipher based on the arithmetic operations after the modulo, which involves the use of the combined deployment of keys and pseudorandom tying blocks of data, which increases level of stability to the block cipher known cryptographic attacks by complicating the analysis in 2^p and 2^N times, respectively. The structure of specialized processors for the block cipher are proposed and provide a speed boost over encryption implementation based on the universal chip in L times. The method for the symmetric block cipher based on arithmetic modulo by using one of the components of the secret key as a module are improved; practical results - software tools and structures of specialized processors that implement the methods of a symmetric block cipher based on arithmetic modulo are proposed; It gives an opportunity to improve the security of information in computer systems; the degree of implementation - the results have been implemented in PLC "VIATEL", firm "VINBUDIZOL" and in the scientific process of VNTU. Scope of - the production of software and hardware.