Secure key exchange using RSA in extended Playfair cipher technique
Pawan Tiwari, Dr. Rohit Kumar Singhal
In time of internet when we are sending and receiving information over network in presence of third-party n it is very necessary to protect our data from assaulter’s, in series to protect data we are using cryptography algorithms. Day to day new cryptography algorithms are found and re is modification in previous algorithm also. According to key encryption algorithm are of two types. First is symmetric key algorithm and second are asymmetric key algorithms. The proposed work is an example of symmetric key with asymmetric key together. In work I done improvement in play fair matrix technique. I used all rules of basic play fair algorithm with some changes (changes in matrix). The objective of thesis is to secure key of play fair procedure of new extended size16x16 using RSA algorithm. It is a two-stage algorithm. In first stage at sender end, I used rules of matrix 5x5 for making matrix and making cipher text. It makes use of alphabets both lower case and upper-case characters, number and special characters for constructing contents of matrix and after this we use shifting value to rotate matrix. In second stage, RSA public key encryption technique is used for sending key of play fair ciphers securely and by this key we make play fair matrix at receiver end.