Just thought I'd mention to those who do not already know... 128-bit WEP encryption is JUST as insecure as 64-bit WEP encryption. Why?
WEP encryption uses a key and an Initialization Vector (IV). 64-bit WEP uses a 40-bit key and a 24-bit IV. 128-bit WEP uses a 104-bit key and a 24-bit IV. So, you see, they both use a 24-bit IV.
The IV is a one-up generated value that is unique to each packet and is sent in the clear. And, because there are only 16,777,216 possible IV values, they will eventually be reused.
The problem occurs when two packets with the same IV value are captured. When this happens, an attacker can easily decipher the key - regardless of whether it is a 40-bit or 104-bit key. As alluded to earlier, IV reuse occurs quickly with increased network use... Send 17 million packets, and a match WILL be made.
What makes matters worse is that when many wireless cards are reinitialized (upon reboot, etc.), the IV is reset to "0" (and the one-up system begins again)... thereby making it easier to capture a duplicate IV. Kill the electricity (or wait for a reboot), then kill the electricity again (or wait for another reboot)... BAM! Instant IV duplication - and the key falls out.
After the key has been discovered, an attacker can then decrypt or spoof packets... and the target will be unaware until an active attack is launched.
M4H ain't just measuring his e-penis, folks. In this instance, he speaks the truth.