Statistical Attack on RC4

Abstract

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 2 43 and advantage 0.5 which uses 2 40 packets. Then, based on several partial temporary key recovery attacks, we recover the full 128-bit temporary key by using 2 38 packets. It works within a complexity of 2 96 . So far, this is the best attack against WPA. We believe that our analysis brings further insights on the security of RC4.

A Survey on RC4 Stream Cipher

“…As reported in the literature the adversary attack the WEP protocol by recovering the secret key K from the known values of IV (initialization vector) and known values of the RC4 keystream bytes found from the plaintext and ciphertext pairs. [31][32][33], and Shepehrdad, Susil, Vaudenay and Vuagnoux (SSVV) attack [34], WEP was declared as an insecure protocol. Later it is replaced by WPA (Wi-Fi protected access) which also make use of RC4 as its core element.…”

“…WPA defended against many attacks in WEP. WPA has again proved to be a weak protocol due to TB data injection attacks [30], and SVV attacks [33]. Further a new protocol WPA2 was proposed by the Wi-Fi alliance which uses AES block cipher as an encryption algorithm instead of RC4.…”

Smashing WEP in a Passive Attack

“…Indeed, tools such as Aircrack-ng are massively downloaded to provide a good example of weaknesses in cryptography. Finally, the TKIP protocol used by WPA is not much different from WEP (just a patch over WEP), so that attacks on WEP can affect the security of networks using TKIP, as seen in [2,26]. For instance in [26], the authors used exactly the same biases as in WEP to break WPA.…”

“…Finally, the TKIP protocol used by WPA is not much different from WEP (just a patch over WEP), so that attacks on WEP can affect the security of networks using TKIP, as seen in [2,26]. For instance in [26], the authors used exactly the same biases as in WEP to break WPA. Hence, gaining a better understanding of the behaviour of these biases may lead to a practical breach of WPA security in future.…”

“…-In Eurocrypt 2011 [26], we presented an attack on WEP by optimising all the previous known attacks in the literature and by introducing a few new correlations. As a result, we claimed theoretically that using 4 000 packets, our analysis provides a success probability of 50% to break WEP.…”