Of course, the fact that data is being broadcast via radio waves rather than transmitted over a wire introduces security challenges, namely:

• How can you prevent user credentials from being hijacked during authentication negotiation?
• Once authentication is complete, how can you protect the privacy of the data being transmitted between client and access point?
• How can you make sure the authorised user connects to the right network?

Early WLAN Implementations

The first WLAN implementations - designed primarily for home use - did little to address these security issues. 802.11b, published in 1999, was the first IEEE draft outlining specifications and protocols for WLAN connections with LAN-equivalent speed and security. More popularly known as Wi-Fi (wireless fidelity), 802.11b provides for wireless transmission rates of 11Mbps.

In 802.11b WLAN solutions, user authentication happened in the clear, via the WLAN device's unique Media Access Control (MAC) address. Each AP contained a database of each authorised client's MAC address; if the client's MAC address was present in the AP's database, the user was granted access to the network. Of course, this left a user's MAC address exposed: anyone sniffing the network could see a valid MAC address being broadcast (and re-set his own device to that address). Also, if the user's client device were stolen, the thief would have all the credentials he or she needed to easily access the network (without having to know or guess a username and password).

In addition to the security problems this method introduced, it also didn't scale well. The MAC address for each user must be stored on each AP on the wireless LAN, creating a cumbersome management scenario and increasing the possibility of security breaches due to administrative oversight.


Data privacy was provided for via a sub-protocol called wired equivalent privacy, or WEP, intended to provide the same level of security found in a wired LAN. As it turned out, first-generation implementations of WEP did not provide this level of security. In fact, numerous published reports, the latest prepared by AT&T, demonstrated convincingly that WEP was easily cracked, seriously breaching the privacy of any wireless data transmission.

The 802.1X Solution

802.1X is a next-generation draft of IEEE WLAN specifications and protocols written to address the security and management pitfalls of 802.11b. The 802.1X protocol provides sub protocols and methods for better protecting authentication and data transmission, including: