Statistical Attack on RC4

Abstract

In this paper we construct several tools for manipulating pools of biases in the analysis of RC4. Then, we show that optimized strategies can break WEP based on 4 000 packets by assuming that the first bytes of plaintext are known for each packet. We describe similar attacks for WPA. Firstly, we describe a distinguisher for WPA of complexity 243 and advantage 0.5 which uses 240 packets. Then, based on several partial temporary key recovery attacks, we recover the full 128-bit temporary key by using 238 packets. It works within a complexity of 296. So far, this is the best attack against WPA. We believe that our analysis brings further insights on the security of RC4.