Enhancing Security of Vigenere Cipher by Stream Cipher

Abstract

Cryptography is a science of converting clear message into secret message "nonreadable message", where message was encrypted at sender side then decrypted at receiver side. Vigenere is an example of substitution cipher, it has various limitations, in this paper we propose an advanced encryption algorithm which improves the security of Vigenere method by combining it with modern cipher method like Stream cipher, Stream cipher relatively regards as unbreakable method, and it uses binary form (instead of characters) where the Plaintext, Ciphertext and the Key are strings of bits. When applying the proposed algorithm, we see that the mentioned above combination cipher has a high degree of security, where cipher based on just Vigenere method is not secure. Also, the proposed algorithm makes the cryptanalysis, using frequency attack, more difficult.

Cipher Craft: Design and Analysis of Advanced Cryptographic Techniques for Secure Communication Systems

“…The Vigenère cipher was adjusted by including punctuation, erratic digits, and scientific imagery in [11]. The suggested approach used scientific graphics, punctuation, and numbers as keys instead of letters to make it harder for an animal power attack.…”

File Cryptography Optimization Based on Vigenere Cipher and Advanced Encryption Standard (AES)

“…The Vigenere square is used to make the encryption process with the Vigenre Cipher easy. The leftmost column of the square declares the key character, but the topmost row declares the plaintext character [5], [10], [16]. Each line in the square declares a character.…”

“…Vigenere is an algorithm that is used to encrypt data or messages in a way, data or information will be encoded using a keyword (Key) in the form of a word. Each alphabet in the data or information is matched exactly with the alphabet contained in the specified keyword, then the encryption or encryption process is carried out [10]. The Vigenere Cipher in essence is almost the same as the basic Caesar Cipher, namely using encoding or encryption every letter in plaintext becomes another alphabet in ciphertext.…”