Abu U. Synthesis and calculation methods of special class Boolean functions for data security means

Thesis is dedicated to a problem of research the ways to increase the data security means efficiency by using Boolean function transformations based on special class functions. New class of Boolean functions is suggested. Being balanced and nonlinear the class functions satisfy strict avalanche criterion. The class properties are invariant for any class functions linear combination. Class functions can be effectively calculated by means of bit operation unification with concurrent execution. New synthesis method of balanced nonlinear SAC-functions is given. Cascade construction method of the Boolean function transformations is proposed as well. Unlike other methods this one allows varying transformations' nonlinearity with its computation complexity. Also the Cascade method can be used for large block transformations construction. New calculation method for Boolean function of suggested class is proposed. The method has linear computational complexity that allows increasing efficiency of data security means by large block transformation utilization.