1. Taras Shevchenko National University,Faculty of Mechanics and Mathematics,Department of Integral and Differential Equations,Kyiv,Ukraine
2. Taras Shevchenko National University,Faculty of Information Technology,Department of Cyber Security and Information Protection,Kyiv,Ukraine
3. Taras Shevchenko National University,Faculty of Information Technology,Kyiv,Ukraine
4. Educational and Scientific Institute of Information Technologies State University of Telecommunications,Kyiv,Ukraine