[Martin Beck] and [Erik Tews] have just released a paper covering an improved attack against WEP and a brand new attack against WPA(PDF). For the WEP half, they offer a nice overview of attacks up ...

When TKIP encryption is used, a message integrity code is included to make sure that the data is not spoofed. It replaces WEP's weaker packet guarantee, which is called cyclic redundancy check.