A Novel Encryption Approach Based on Vigenère Cipher for Secure Data Communication

Abstract

Nowadays, with the advancement of technologies in modern life communication and networks, the secrecy of a cryptographic technique has become a strong necessity. The Vernam’s cipher which is a specific form of Vigenère cipher is gaining attention of researchers in the cryptography. But the modern encryption methods based on matrices available in the literature have their limitations to utilize them. Therefore, motivated by numerous cryptographic techniques available in the literature, this study presents a novel encryption approach for secure data communication. The proposed encryption approach is based on Vigenère cipher in finite dimensional vector space. Furthermore, the proposed approach relies on an eternal decomposition which is indiscriminate in the key selection inside key space. To add complexity by text scrambling, a weird substitution cipher key is added to provide maximum derangement in the encrypted text structure. Additionally, in the lights of Shannon’s secrecy, a comparison with usual matrix methods relying on $LU$—decomposition and eigenvalue decomposition is also discussed to justify the perfect secrecy thus achieved. It is revealed that the proposed encryption approach is a more versatile and perfectly secret encryption scheme that roots on the widening of key space to a mathematical structure, which not only fulfills the completeness with respect to the proposed decomposition but identical to message space as well.