[1] Newsham is best known for co-authoring the paper Insertion, Evasion and Denial of Service: Eluding Network Intrusion Detection[2] with Thomas Ptacek, a paper that has been cited by more than 150 academic works on Network Intrusion Detection since.
The Newsham 21-bit attack is a method used primarily by KisMAC to brute force WEP keys.
It is effective on routers such as Linksys, Netgear, Belkin, and D-Link but does not affect Apple or 3Com, as they use their own algorithms for generating WEP keys.
Using this method allows for the WEP key to be retrieved in less than a minute.
This method is 2^19 times faster to brute force than a 40-bit key would be, allowing modern processors to break the encryption rapidly.