Developing a Modified Hybrid Caesar Cipher and Vigenere Cipher for Secure Data Communication

Abstract

Many Ciphers have been developed to provide data security. This paper sets out to contribute to the general body of knowledge in the area of classical cryptography by developing a new modified hybrid way of encryption of plaintext. Using of large key spaces with huge number of rounds with multiple complex operations may provide security but at the same time affects speed of operation. Hence in this paper, a modified hybrid of Caesar Cipher and Vigenere Cipher with diffusion and confusion which Classical ciphers cannot boast of is proposed. The Caesar Cipher and Vigenere Cipher have been modified and expanded so as to include alphabets, numbers and symbols and at the same time introduced a complete confusion and diffusion into the modified cipher developed. Classical ciphers can be made effective and used for providing security by adding the properties possessed by the modern ciphers. In this paper, the characteristics of modern cipher were incorporated to classical cipher. Thus the proposed Scheme is a hybrid version of classical and modern cipher properties in which the modified hybrid of both the Caesar Cipher and Vigenere Cipher is now made a very strong cipher and difficult to break using a frequency method, brute force, etc.

Keywords: Encryption, Decryption, Substitution, Cipher, Random Number, Recursive, Primitive Root, Plaintext, Cipher Text, Optimization