Algebraic Analysis of Cryptographic Security Systems
The research of algebraic cryptanalysis method was carried out in this work. Systems of the equations for tables of various sizes of nonlinear transformations of substitution for simplified model of GOST28147-89 algorithm are received, also we solve a one of this systems by a XL method. During this work we produced a program, which has realised a generation and solving of system of equations describing nonlinear transformations of substitution. We analysed a nonlinear systems of equations and calculated a value of complexity of XL method for eight blocks of substitution.