Wireless Home Networking - Index of

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Part III: Installing a Wireless Network
With most wireless network systems, you take care of both functions with a
single step — the assignment of a network key or passphrase (we explain later
in this chapter, in the section “Enabling encryption,” where each of these is
used). This key or passphrase is a secret set of characters (or a word) that
only you and those you share it with know.
The key or passphrase is often known as a shared secret — you keep it secret
but share it with that select group of friends and family whom you want to
allow access to your network. With a shared secret (key or passphrase), you
perform both of these security functions:
� You authenticate users because only those who have been given your
supersecret shared secret have the right code word to get into the network.
Unauthenticated users (those who don’t have the shared secret)
cannot connect to your wireless network.
� Your shared secret provides the mechanism to encrypt (or scramble) all
data being sent over your network so that anyone who picks up your
radio transmissions sees nonsensical gibberish, not data that they can
easily read.
The two primary methods of providing this authentication and encryption are
� Wired Equivalent Privacy (WEP)
� Wi-Fi Protected Access (WPA)
Note that there are two versions of WPA, WPA and WPA2, but we refer to
them jointly as WPA except when discussing their differences.
We talk about the WEP and WPA security systems in more detail in the remaining
parts of this chapter. WEP, an older system, provides only a limited amount
of security because certain flaws in its encryption system make it easy for
crackers to figure out your shared secret (the WEP key) and therefore gain
access to your network and your data.
WPA is the current, up-to-date, security system for Wi-Fi networks (there are
several variants, which we discuss later in this chapter), and it provides you
with much greater security than does WEP. If you have the choice, always use
WPA on your network rather than WEP.
The shared secret method of securing a network is by far the most common
and the easiest method. But it doesn’t really provide truly bulletproof user
authentication, simply because having to share the same secret passphrase
or key with multiple people makes it a bit more likely that somehow that
secret will get into the wrong hands. (In fact, some experts would probably
hesitate to even call it an authentication system.)