WPA is a very secure encryption method that is now preferred for
computers that can use it. WEP is an older encryption method that is less secure, but it is useful if your network has systems that are not WPA capable.
Mac OS X 10.3 or later automatically recognizes if the network you are joining uses WEP or WPA, and it gives you the correct prompt. This is the one you see for WEP:
If you join a WPA network, Mac OS X 10.3 or later shows you this prompt:
In addition to being much more secure, WPA is also easier to use. WPA works best in Mac OS X 10.3.3 or later with AirPort software 3.3 or later.
There are two ways to set up WPA, Personal and Enterprise. WPA Personal is easier to set up if you have a small network, such as in your home. You would set it up using AirPort Admin Utility, much as you may have for WEP in the past.
For a school or business, WPA Enterprise can provide each user with unique credentials. WPA Enterprise uses the same security as WPA Personal, but with the added measure of individual usernames and passwords (WPA Personal uses a shared password). Each wireless base station communicates with a RADIUS server to authenticate the user's credentials. When joining a WPA Enterprise network, Mac OS X 10.3 or later would give you this prompt that includes username and password:
The basis of WPA Enterprise is 802.1X, which can be used with either wired or wireless networks. It requires more extensive knowledge to set up than WPA, which is advertised by the wireless access point. If you encounter the older "802.1X Authentication" method, the user will be prompted with a WEP password dialog box. The 802.1x Authentication method is not recommended, because it uses a static key and is less secure. You may need the help of a network administrator to join an 802.1x network.