Enhanced Hill Cipher Algorithm with Novel Encoding and Key Generation

This research article presents a modified Hill Cipher algorithm that incorporates a novel alphanumeric encoding scheme, for the extended character set that includes alphabets, digits, and space characters. It employs a novel non-sequential encoding scheme aims to provide enhanced security by avoiding predictable character mapping. It also uses a novel approach to key generation, employing a random selection of numbers within a specific range of digits, which significantly accelerates the key generation process faster than the traditional Hill Cipher algorithm. With a character set of 37 (alphabets (26), digits (10) and space), the prime modulus 37 is used in the Hill Cipher, which eliminates the need for the GCD check, that helps in lowering the computational complexity. Further, it has been found that the proposed Hill Cipher provides enhanced efficiency, security, and versatility by generating varied cipher texts for the same character and same cipher text for different plaintext characters.