Analysis On The Security Of RC4 Algorithm

With the rapid development of mobile communication technology and information security technology, stream cipher algorithms are widely used in many fields. RC4 algorithm as the represented stream cipher algorithm has some advantages such as it is flexible and fast in computing. It is used to encrypt the data in WEP (Wired Equivalent Privacy) which is a part of standard in IEEE802.11 wireless LAN. However, many researchers suspect the security in WEP due to the weaknesses of RC4 algorithm itself.Firstly, we describe the principles of RC4 algorithm and present the methods based on WEP which are the most effective methods to analysis the security of RC4. Secondly we present a new method according to the existing theoretical results as following. We prove that there are correlation between the input key and cipher text according to the Probability Theory. Then we compute the complexity by the information theory. We take the new method to ARP (Address Resolution Protocol) and showed the result of attacking. Finally, there are two new analysis models showed which are improved based on our new method. The first one is based on the second round of the output in key stream and the second one is cipher text only analysis. In addition, we present the complexity of those methods and discuss the factors that affect our attack.