Design and Analysis of Playfair Ciphers with Different Matrix Sizes

Abstract

Playfair cipher is an interesting data encryption technique with a medium level of complexity, and therefore, is suitable for security of wireless and mobile systems. Different sizes of the matrices used for key have been prevsiouly stuided by researchers, but no study has been done so far that provides a comparative analysis of different matrix sizes of a key. This paper is motivated by this observation, and provides a comparison of three different matrix sizes used for the key. These matrices are 9 x 9, 10 x 10, and 11 x 11. Different experiments were performed which indicate that for the data used herein, the size of the plaintext does not have a signifncicant effect on the encryption of the output. However, the size of the key does have a notable effect and the exntrypion level increases with big keys of bigger sizes. Furthermore, increasing the size of the matrix provides better encryption results.