Over the past year, veteran certification (and Pearson) author Emmett Dulaney has pushed out a peachy series of what he calls "Visual Guides" to information security. Previous efforts have covered risk management, phishing, and social engineering. His latest visual guide does a fabulous job of depicting and explaining various wireless security standards, including such alphabet soup as WEP, WPA, and WPA2.
Dulaney uses a simple set of pictures of doors to get the principles of wireless security standards across. In his article entitled "A Visual Guide to Wireless Secuirty Standards," he tackles this topic from the perspective of coverage for the recently revised Security+ exam (SY0-301). This exam features a great increase in its coverage of wireless security topics, entirely in keeping with the burgeoning presence of wireless components in networks everywhere nowadays.
WEP (Wired Equivalent Privacy) is likened to a simple interior house door with nothing beyond a simple button lock that can easily be jimmied or forced open. He uses this metaphor to explain how WEP is weak, relatively insecure, and easily broken or exploited.
WPA (Wi-Fi Protected Access) strengthens the door with a simple slide lock. The analogy here is that it strengthens the WEP system by adding another layer of stronger security, and stronger encryption. Dulaney also explains the use of the Temporal Key Integrity Protocol (TKIP) which also regularly and frequently changes encryption keys as an important way to boost security for the WPA security standard.
Continuing his visual analogy, Dulaney then depicts a door with a keyed deadbolt to denote WPA2 (aka Wi-Fi Protected Access 2) which adds support for the IEEE 802.11i wireless security and even requires newer wireless networking hardware (or at least upgraded firmware) to do its thing completely and properly. A close look at this example door also shows a protected catchplate on the locks, so that they are difficult if not impossible to force, and a second complete locking mechanism to lock everything down twice.
Dulaney does a great job with these analogies and images, not only because he offers clear and simple technical explanations, but also because he provides simple, intelligible images that are easy to remember to fix all that information in your mind. I wish this kind of material were available for the whole infosec curriculum: It would have it much faster and easier for me to do my CISSP work.