Modification of Vigenère Cipher to Overcome Kasiski and Friedman Attacks

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.