RK-CIPHER Encryption Algorithm

Poly-alphabetic substitution cipher is one of the strongest methods of encryption. This paper presents an alternate algorithm for poly-alphabetic substitution cipher. This method can be encrypted in a different way for different part of the data. The name, RK(Random-number to Key alphabets) cipher goes with its key functionality of assigning a random number to all the alphabets of key which further will be used for rotation and encryption of plain text in which the cryptographic technique is poly-alphabetic substitution, where multiple alphabets are substituted for a single alphabet in the plain text for different keys. In the conventional vigenere cipher the letters of key is assigned to letters of plaintext respectively and this is repeated at the intervals equal to the length of the key, where-as in this paper, each letter of the key is associated with a random number which decides the circular shifting or rotation of the disk in simple words. Index terms- Cipher, poly-alphabetic substitution, plain-text, encryption, decryption, key.