Enhancement of Known IV attack for WEP-like Systems

Abstract

Wired Equivalent Privacy (WEP) protocol is used to assure the privacy of IEEE 802.11a/b based on RC4 stream cipher. Fluhrer [1] proposed the known IV attack using the first output of RC4 in WEP to derive the secret key. However, if one avoids the usage of the first output of RC4, the attacker will get nothing using this type of attack. In this paper we extend the known IV attack to use other outputs of RC4. We also use the different outputs of RC4 simultaneously to reduce the required number of weak IVs in the known IV attack from 60 to 48 for 50% successful probability of deriving the secret key.