Proposal of a Secure WEP Operation against Existing Key Recovery Attacks and its Evaluation

Abstract

WEP is a security protocol in a wireless LAN network. However its vulnerability has been pointed out, and many key recovery attacks against WEP were proposed by using it. Some attacks can retrieve a WEP key easily by observing about 20,000 packets. In order to avoid such attack, we have to update the WEP key whenever the number of communicated packets exceeds a certain threshold. For immunizing against key recovery attacks, it is the best way to update the key every 10,000 packets. However 10,000 packets are very few, so it is not realistic. In this paper, we propose a secure WEP operation against key recovery attacks. The proposed method requires for attackers at least 100,000 packets to recover the WEP key. Furthermore we theoretically evaluate our technique to operate a secure WEP communication.