Play fair algorithm

Playfair cipher is an interesting data encryption technique with a medium level of complexity, and therefore, issuitable for security of wireless and mobile systems. Different sizes of the matrices used for key have been previously studied 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 x9, 10 x 10, and 11 x 11.Different experiments were performed which indicate that for the data used herein, the size of the plain-text does not have a significant effect on the encryption of the output. However, the size of the key does have a notable effect and the encryption level increases with big keys of bigger sizesPlayfair密码（Playfair cipher）是一种兼具趣味性与中等复杂度的数据加密技术，可适用于无线与移动系统的安全防护。此前已有研究者针对密钥所采用的不同尺寸矩阵展开研究，但截至目前尚无相关研究对密钥的不同矩阵尺寸开展对比分析。受此启发，本文针对三种不同尺寸的密钥矩阵展开对比研究，所用矩阵分别为9×9、10×10及11×11。 本研究开展了多组实验，结果表明，针对本文所用数据集，明文尺寸对加密输出结果无显著影响；而密钥尺寸则会产生显著影响，且加密强度随密钥矩阵尺寸的增大而提升。