How WEP Works

Overview

Were it not for the security issue, there'd be a whole lot less to say about Wi-Fi. Wires make for reasonable security: Unless you can physically access the wires (and thus tap into them) a wired network is much, much more secure, at least from outsiders. (Subversion from legitimate insiders is a whole different question.)

Radio waves change everything. People sitting out in the street can 'listen' to your Wi-Fi network with packet sniffers, and if your network is wideopen and unprotected, they can connect to your network and use it without your knowledge or permission. Maybe they just want to surf the Web on somebody else's nickel-or maybe they're looking for an opportunity to commit IP impersonation, during which they may commit a crime or do other obnoxious things while making it look like the perpetrator is you.

Wired Equivalent Privacy (WEP) was created to protect against such problems. As you've no doubt heard, WEP is flawed, and can be cracked by hackers using free tools like AirSnort. The press on WEP has been mostly bad, but the truth is much more complex. WEP is far more useful than people make it sound, and at least until the new Wi-Fi Protected Access (WPA) standard becomes available (it likely could be by the time you read this book), WEP is about all the home or small office user can do to protect a Wi-Fi network.

WEP is a program that runs in your access point's firmware, as well as in the firmware of all client adapters that connect to your access point. All Wi-Fi compliant hardware devices must have WEP available in a compatible form. Some manufacturers have extended WEP to make it more secure, but those extensions are not standardized, and if you use the extensions you may not be able to make hardware from different vendors intercommunicate. Be aware that the WEP standard defines only 64-bit encryption. The very common 128-bit encryption feature is a WEP extension and may not work identically on equipment from different vendors! (I'll have more to say on these misleading bit-length encryption numbers later on. As usual, all is not what it seems.)