Cryptanalysis on modified Vigenere using bipartite graph

Abstract

In the recent digital era of data transmission and network operations, data security and safety are some of the biggest challenges faced by the mankind. Cryptography is the study of encryption and decryption, the procedure of converting data into a format which prevents the unauthorized parties to access, analyse or change the shared data. An increasing number of studies demonstrating new approaches of Cryptography can be found in this area. Among these, one of the most burgeoning approaches of Cryptography is Graph Theory. Various graphs with their unique properties have been implemented in the cryptographic algorithms which have effectively resisted the unwanted parties from interfering. Vigenere Cipher is one of the most secured encryptions which adapts the concept of substitution cipher. An algorithm with the concept of Vigenere Cipher along with Bipartite Graphs has been proposed in this paper. The existing Vigenere Cipher has only 26 alphabets which limits the eligibility of the data types with only the uppercase alphabets. In this algorithm a modified Vigenere table has been proposed with all the characters with ASCII values, covering a wide range of all kinds of texts. This work enables security, authenticity and confidentiality of the shared information with the bipartite graph characteristics like vertex partitioning, edge weighting etc. The XOR operations used in this work ensures more security. All the security procedures ensures to prevent some of the most threatening third party attacks ( for example, Brute Force Attack, Plaintext attack, ciphertext only attack etc.).