Conversion of Stream Cipher into Block Cipher

Abstract

In the time of internet when we are sending and receiving the information over the network in the presence of the third party then it is very necessary to protect our data from the attacker’s, in the series to protect the data we are using the cryptography algorithms. Day to day the new cryptography algorithms are found and there is modification in the previous algorithm also. The proposed paper is an example of the converting the stream cipher into the block cipher. In this paper I taken the Playfair example is as the stream cipher, and tried to convert into the block cipher. This is also an example of the symmetric key algorithm. This is a two steps algorithm. In first step, I taken the 5x5 matrix that is traditional Playfair matrix of 26 characters and I take a second matrix of 5x5 of words. For converting the plain text into cipher text first of all se the plain text pair in the first matrix according the position of these character’s we replace the words from the second matrix. I used the all rules of traditional Playfair algorithm.