Maximum Wireless Security

IV Collision

WEP uses a value known as an initialization vector, commonly called the IV. The RC4 algorithm uses this value to encrypt each packet with its own key. It does this by merging, or concatenating, the preshared password with the IV to create a new and exclusive “packet key” for each and every packet of information sent over the WLAN.

However, if the sending party uses an IV to encrypt the packet, the receiving party must also know this bit of information to decrypt the data. Because of the way WEP was implemented, this requirement turned an apparent strength into a weakness. Let’s discuss this in more detail.

IV Explanation

WEP uses a three-byte IV for each packet of data transmitted over the WLAN. When the data is sent, the IV is ...