Senthilkumar G, “Modified Version of Playfair Cipher Using Linear Feedback

In this paper we present a new approach for secure transmission of message by modified version of Playfair cipher combining with Random number generator methods. To develop this method of encryption technique, one of the simplest methods of random number generator methods called Linear Feedback Shift Register (LFSR) has been used. Playfair cipher method based on polyalphabetic cipher. It is relatively easy to break because it still leaves much of the structure and a few hundred of letters of ciphertext are sufficient. Here we are mapping random numbers to secret key of Playfair cipher method and corresponding numbers will be transmitted to the recipient instead of alphabetical letter. This method rapidly increases security of the transmission over an unsecured channel. Keywords