Paper Title
A New Cryptosystem Based On Polyalphabetic Substitution Scheme With Multiple Number Of Vigenere Table

Abstract
In order to provide secure communication different cryptographic techniques are available. Two basic building blocks of all encryption techniques are substitution and transposition. Polyalphabetic cipher is based on substitution, the plaintext letters are encrypted differently depending upon their placement in the text. Vigenere cipher is considered to be most efficient and simplest polyalphabetic substitution cipher. Due to its repeating nature of the keyword, it is also vulnerable to attacks. To overcome this, here we are presenting a new cipher which uses multiple Vigenere Table for encryption. In this proposed cipher the keyword is repeating until it is equal to the length of the plaintext. But each time keyword repeats the cipher uses different Vigenere Table for encryption and the new Vigenere Table is generating from the previously used one.