International Journal of Computer Applications
In this paper, the authors explain about encryption and decryption of text using a secret password provided by the user. The encryption machine takes the password and source message as input and generates a cipher text based on modified Playfair Cipher algorithm using dynamic rectangular matrix. The decryption machine takes the same password and the cipher text generated by the encryption engine as input to produce the original message. It also checks if the input is valid and blocks the user when an invalid input is provided. In this paper, the entire program will be simulated by using an PHP application.