Dummies, Wireless

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Part III: Installing a Wireless Network
How about a bit more about WEP?
WEP encrypts your data so that no one can read it unless they have the key.
That’s the theory behind WEP, anyway. WEP has been a part of Wi-Fi networks
from the beginning. (The developers of Wi-Fi were initially focused on
the business market, where data security has always been a big priority.) The
name itself belies the intentions of the system’s developers; they wanted to
make wireless networks as secure as wired networks.
To make WEP work, you must activate it on all the Wi-Fi devices on your network
via the client software or configuration program that came with the
hardware. And every device on your network must use the same WEP key
to gain access to the network. (We talk a bit more about how to turn on WEP
in the later section, “Clamping Down on Your Wireless Home Network’s
Security.”)
For the most part, WEP is WEP is WEP. In other words, it doesn’t matter
which vendor made your access point or which vendor made your laptop’s
PC Card network adapter — the implementation of WEP is standardized
across vendors. Keep this one difference in mind, however: WEP key length.
Encryption keys are categorized by the number of bits (1s or 0s) used to
create the key. Most Wi-Fi equipment these days uses 128-bit WEP keys, but
some early gear (such as the first generation of Apple AirPort equipment)
supported only a 64-bit WEP key.
Many access points and network adapters on the market support even longer
keys — for example, many vendors support a 256-bit key. The longest standard
key, however, is 128 bits. Most equipment enables you to decide how
long to make your WEP key; you can often choose between 64 and 128 bits.
Generally, for security purposes, you should choose the longest key available.
If, however, you have some older gear that can’t support longer WEP
key lengths, you can use a shorter key. If you have one network adapter that
can handle only 64-bit keys but have an access point that can handle 128-bit
keys, you need to set up the access point to use the shorter, 64-bit key length.
Should you use WEP?
WEP sounds like a pretty good deal, doesn’t it? It keeps your data safe while
it’s floating through the ether by encrypting it, and it keeps others off your
access point by not authenticating them. But, as we mention earlier in this
chapter, WEP isn’t all that secure because flaws in the protocol’s design make
it not all that hard for someone to crack your WEP code and gain access to
your network and your data. For a typical home network, a bad guy with the
right tools could capture enough data flowing across your network to crack
WEP in a matter of hours.