As usage of network applications are increasing rapidly, the need to protect these applications has also been
increased. Cryptography is the most popular solution to secure information which provides privacy for the users by
securing message with encryption. Various encryption techniques have been proposed so far. Vigenere cipher is a
polyalphabetic cipher which was used earlier. But its security was broken by determining repeating segments of the
Ciphertext. To enhance the security of Vigenere cipher a lot of modifications have been proposed so far. Here we
propose an idea where Vigenere cipher is modified by left circular shift (LCS) of the shared private key to make it
harder to analyse. Then it is modified using elliptic curve cryptography (ECC) which is being considered as a
replacement for RSA that needs larger key length. LCS creates a dynamic key. Encryption with this dynamic key
using Vigenere cipher and then modification using ECC ensures improved efficiency and also provides better
security which is harder to break.