An efficient algorithm for polyalphabetic substitution using random tables

There are many cryptographic techniques available for providing a secure communication. Encryption technique can be classified according to their encrypting process. They are substitution cipher and transposition cipher. Polyalphabetic cipher is based on substitution technique- the plaintext letters are encrypted differently depending upon their placement in the text and the keyword. Vigenere cipher is considered to be the most efficient and simplest Polyalphabetic substitution cipher. Due to its repeating nature of the keyword, it is vulnerable to attacks. To overcome this, here we are presenting a new cipher which uses multiple random Tables (26×26) for encryption. In this proposed cipher, for encrypting each plaintext letter we are generating a random table (26×26). Instead of using the same Vigenere table here we are using an infinite number of alphabetical tables depending on the length of the plaintext. Also, each table will be completely independent from the previous table. The repeating nature of the keyword does not help the crackers to break this code. So this proposed polyalphabetic cipher is unbreakable.