Scientific paper ID 869 : 2013/3

This publication describes the developed training module with graphical user interface for encryption and decryption of texts in English or Bulgarian, which will be used in the course “Telecommunications Security” d as compulsory in the curriculum of the specialty “Telecommunication Systems” for the “Bachelor” educational qualification degree in University of Ruse “Angel Kanchev”. The training module is implemented using MATLAB and GUIDE (Graphical User Interfaces Development Environment). The application allows to choose keywords from the pop-menu for constructing the “squares” of the ciphertext, to illustrate the process of encryption/decryption of plaintext/cipher-text entered in the text box by the user using two-square or four-square ciphers based of Playfair cipher. The “squares” used for encryption/decryption are displayed in the graphical axes. Both varieties of the two-square ciphers are implemented – horizontal and vertical. There is an opportunity information about the applications of the ciphers as well as the principle of operation of the cipher to be displayed in a separate graphical window, if desired by the user. The developed training module aims to increase students" interest in studying the course “Telecommunication security”.