An Enhanced Key Security of Playfair Cipher Algorithm

Cryptography is one of the best methods to keep the information safe from security attack by unauthorized people. At present, many studies had been conducted to generate a more robust cryptographic algorithm to provide high security for data communication. In this study, the authors proposed an enhanced key security of Playfair cipher algorithm using Playfair cipher 16x16 matrix, XOR, two's complement, and bit swapping. The result of the study shows that the processing time for encryption and decryption processes are linearly proportional. It means the longer characters of the key; the more significant times needed to encrypt and decrypt the key. Also, the proposed method is faster than the existing key security of Playfair cipher algorithm. Experimental results also show that the proposed key security algorithm exhibits strong avalanche effect. It was also found that the key cannot be easily cracked by an attacker performing brute-force attack.