Abstract

Protecting data from malicious attacks during storage and transmission is the reason for using encryption. Encryption can be achieved by two methods – Transposition and Substitution. Transposition refers to changing the order of characters in a given text. On the other hand, substitution is the process of replacing each character of the plaintext with some other character. Using a combination of transposition and substitution for encryption leads to greater security when compared to using either of them separately. Vigenère Cipher is a poly-alphabetic cipher. It is based on the substitution technique which uses multiple substitution alphabets. In this paper, we introduce double columnar transposition on Vigenère Cipher to enhance its security making cryptanalysis difficult.

References

• Atul Kahate (2009), Cryptography and Network Security, 2nd Edition, McGraw-Hill.
• Overview of Cryptograhy-http://www. garykessler. net/library/crypto. html.
• William Stallings: "Cryptography and Network Security: Principles and Practices" 4th Edition,
• Martin, Keith M. (2012). Everyday Cryptography. Oxford University Press. p. 142. ISBN 978-0-19-162588-6.
• Cryptanalysis of Vigenère Cipher-http://www. nku. edu/~christensen/section%2012%20vigenere%20cryptanalysis. pdf
• Abdul Razaq ,Yasir Mahmod, Faroq Ahmed, Ali Hur : Strong Key Machanism Generated by LFSR based Vigenère Cipher – 13th International Arab Conference on Information Technology (December 2012)
• Yumnam Kirani Singh :Generalization of Vigenère Cipher - ARPN Journal of Engineering and Applied Sciences (January 2012)
• Alpha-Qwerty Cipher: An Extended Vigenère Cipher-Advanced Computing, An International Journal, Vol. 3, No. 3, May 2012.