ENHANCING COMPUTATIONAL TIME FOR A 16X16 PLAYFAIR MATRIX FOR UNICODE CHARACTERS

Abstract

Playfair cipher is one of the most popular poly-alphabetic ciphers that can be used suitably for wireless and mobile devices where security requirements are high and system resources are low. The existing work uses a 16x16 playfair matrix for Unicode characters. The 16x16 matrix is used for characters’ representation and a shuffling technique is applied after each character encryption. However, the shuffling technique used and character search in the 16x16 matrix after each character encryption leads to a high computation time. In order to overcome the shuffling and character research of the existing 16 x 16 algorithm, this work used shifting keys to search for character sand shuffle the entire matrix without changing the position of each element in the matrix unlike in the existing work. This paper shows that a 17x17 matrix algorithm performed better in terms of encryption time by 1.29972 seconds and decryption time by 2.76146 seconds on an average. Therefore, an increase in memory to form a 17x17 matrix has a negligible impact on the enhanced algorithm. Also, the enhanced algorithm transforms the plaintext into Chinese characters. These Chinese characters (ciphertext) are seen as plaintext which translates into something meaningful in order to preserve the integrity of the original plaintext and to fend-off suspicious attacker sun like in the previous study where the ciphertext generated are random characters without any meaning. Hence, the enhanced algorithm provides a better way of hiding information.