  This paper develops a new algorithm to improve the security of RC4. Given
that RC4 cipher is widely used in the wireless communication and has some
weaknesses in the security of RC4 cipher, our idea is based on the combination
of the RC4 and the poly alphabetic cipher Vigen\`ere to give a new and more
secure algorithm which we called VRC4. In this technique the plain text is
encrypted using the classic RC4 cipher then re-encrypt the resulted cipher text
using Vigen\`ere cipher to be a more secure cipher text. For simplicity, we
have implemented our new algorithm in Java Script taking into consideration two
factors: improvement of the security and the time complexity. To show the
performance of the new algorithm, we have used the well known network cracking
software KisMac.
