Technology of describing linear and nonlinear cryptographic transformations

The paper deals with the study of the dependence of the calculation of the number of operations, based on recurrent combination of capacities of sets of operations of lower bit rate and elementary functions to describe the process of construction of sets of new operations. The possibility of developing a single technology for the synthesis and investigation of both linear and nonlinear operations of cryptographic transformation of information is studied. An attempt has been made to obtain three-bit operations based on two-bit operations of cryptographic information conversion. For this purpose, logical functions are presented in the form of logical operations of two variables corresponding to them in analytical representation. Two-bit elementary functions in the operation of cryptographic information transformation are combined. The study calculates the number of twobit, three-bit and four-bit elementary functions, two-bit, three-bit and four-bit operations. According to the results of the study, it is found that our proposed dependence of the calculation of the number of operations of cryptographic transformation, based on recurrent combination of capacities of sets of operations of lower bit rate and elementary functions, is correct and mathematically describes the process of constructing the sets of new operations. Based on the results of this study, it can be considered that the development of a single technology for the synthesis and investigation of both linear and nonlinear operations of cryptographic transformation of information is possible. This approach allows not only to calculate the number of operations of cryptographic information conversion, but also to construct the operations themselves by combining known cryptographic transformation operations and elementary higher bit functions. The proposed approach creates the preconditions for the development of a single technology for the description and synthesis of both linear and nonlinear crypto-transformation operations