This paper observes approaches to algebraic analysis of GOST 28147-89 encryption algorithm (also known as simply GOST), which is the basis of most secure information systems in Russia. The general idea of algebraic analysis is based on the representation of initial encryption algorithm as a system of multivariate quadratic equations, which define relations between a secret key and a cipher text...

Abstract In [1] Varsha and Jaferi proposed an iterative method for solving nonlinear functional equations, viz. nonlinear Voltera integral equations, algebraic equations and system of ordinary differential equations. Then Sachin and Varsha [2] implemented this method to solve linear and nonlinear partial differential equations of integer and fractional order. The aim of this article is to propo...

In this paper, we employ Nevanlinna’s value distribution theory to investigate the existence of meromorphic solutions of some algebraic differential equations. We obtain the representations of all meromorphic solutions of certain algebraic differential equations with constant coefficients and dominant term. Many results are the corollaries of our result, and we will give the complex method to f...

In this paper, a new shifted ultraspherical wavelets operational matrix of derivatives is introduced. The two wavelets operational matrices, namely Legendre and first kind Chebyshev operational matrices can be deduced as two special cases. Two numerical algorithms based on employing the shifted ultraspherical wavelets operational matrix of derivatives for solving linear and nonlinear differenti...

We discuss two notions of index, i.e., the geometric index and differentiation for nonlinear differential-algebraic equations (DAEs). First, we analyze solutions DAEs by revising a reduction method (see e.g. Rabier Rheinboldt (2002), Riaza (2008)). Then show that although both serve as measure difficulties solving DAEs, they are actually related to existence uniqueness in different manner. It i...

In this paper, we consider the second-kind Chebyshev polynomials (SKCPs) for the numerical solution of the fractional optimal control problems (FOCPs). Firstly, an introduction of the fractional calculus and properties of the shifted SKCPs are given and then operational matrix of fractional integration is introduced. Next, these properties are used together with the Legendre-Gauss quadrature fo...

Direct algebraic method of obtaining exact solutions to nonlinear PDE’s is applied to certain set of nonlinear nonlocal evolutionary equations, including nonlinear telegraph equation, hyperbolic generalization of Burgers equation and some spatially nonlocal hydrodynamic-type model. Special attention is paid to the construction of the kink-like and soliton-like solutions.