282 Chapter 11 WEP combines the shared key k and the IV v as inputs to seed the RC4 function. 802.11B [6] specifies that the seed shall be 64 bits long, with 24 bits from the IV v and 40 bits from the shared key k. Bits 0 through 23 of the seed contain bits 0 through 23 of the IV v, and bits 24 through 63 of the seed contain bits 0 through 39 of the shared key k. When a receiver receives the ciphertext C, it will XOR the ciphertext C with the corresponding keystream to produce the plaintext M 0 as follows. WPA and WPA2 Wi-Fi Protected Access (WPA) is specified by the IEEE 802.11i standard, which is aimed at providing stronger security compared to WEP and is expected to tackle most of the weakness found in WEP [7­9]. WPA WPA has been designed to target both enterprise and consumers. Enterprise deployment of WPA is required to be used with IEEE 802.1x authentication, which is responsible for distributing different keys to each user. Personal deployment of WPA adopts a simpler mechanism, which allows all stations to use the same key. This mechanism is called the