Modification of Vigenère Cipher to Overcome Kasiski and Friedman Attacks
Ajay Sudhir Bale, Naveen Ghorpade, K Bhagya, Muhammed Furqaan Hashim, H Chandramouli, R Hamsalekha · 2023
Since the advent of wireless communication, the safe transmission of data from one point to another has been of prime significance and concern. As a result, many algorithms have been developed to encrypt the data being transmitted from the sender's side to avoid unauthorized access. Yet, cybercriminals tend to always find loopholes in algorithms and develop a way to bypass or crack encryption to obtain confidential data. Vigenère Cipher is among the oldest and best-known polyalphabetic ciphers, which uses polyalphabetic substitution with the help of a series of Caesar ciphers to encrypt data. Yet, attackers have found ways to crack the encryption by analyzing the frequency of letters and predicting the key. This paper introduces a new methodology to overcome frequency analysis using the transposition of plain text characters based on the value of the characters from the key being used to encrypt them. As a result, Kasiski and Friedman attacks are nullified on the encrypted text.