Enhancing Security of Elliptic Curve Elgamal Encryption using a Polyalphabetic Symmetric Cipher

today's digital world, we are dependent on internet for a variety of things and in many situations we have to disclose our personal information. Preventing an unauthorized person from viewing and using our personal information is a great challenge. Most of the websites where online transactions take place are secured by security protocols. These security protocols use various symmetric key and asymmetric key encryption algorithms. Elliptic curve cryptography is an asymmetric key encryption algorithm which is suitable for encrypting short messages. In this paper we present a method to enhance the security of Elliptic Curve ElGamal System. The security of El Gamal system is improved by using a polyalphabetic cipher at the time of mapping plaintext message to an elliptic curve.