FMS Attack-Resistant WEP Implementation Is Still Broken: Most IVs Leak a Part of Key Information

摘要

In this paper, we present an attack to break WEP that avoids weak IVs used in the FMS attack. Our attack is a known IV attack that doesn't need the specific pattern of the IVs. This attack transforms most IVs of WEP into weak IVs. If we attempt to avoid all weak IVs used in our attack, the rate at which IVs are avoided is too large to use practical. When using a 128-bit session key, the efficiency of our attack is 2~(72.1) in the most effective case. This implies that our attack can recover a 128-bit session key within realistically possible computational times.