Enhancing Playfair Cipher using Seed Based Color Substitution

Encryption is one of the most powerful methods to achieve data security and privacy in terms of viewing or modifying the data. Different techniques such as substitution, shifting, and application of mathematical operations have been used to perform encryption through the generation of different forms of the original data for security and privacy purposes. Data encryption techniques such as Playfair cipher being the first of its kind polyalphabetic encryption technique, which uses digraph/bigram or a pair of letters to encrypt a pair of plaintext, has exhibited strong security over the years. With the advent of computer advancements, many vulnerabilities of the cipher have been made, therefore, to further improve Playfair cipher against attacks such as cryptanalytic, brute force attack, and shoulder surfing, a modified Playfair cipher is presented. The proposed Playfair cipher highlights the integration of randomly generated numbers and color substitution techniques that further strengthens the encryption process, which leads to improved data privacy.