Wi-Fi Protected Access is a Wi-Fi security technology developed in response to weaknesses in Wired Equivalent Privacy standards. It improves on the authentication and encryption features of WEP. WPA2, in turn, is an improved form of WPA; since 2006, every Wi-Fi certified product must use it.
How do WPA and WPA2 work?
WPA provides stronger encryption than WEP by using one of two standard technologies: Temporal key integrity protocol and advanced encryption standard. WPA also includes built-in authentication support that WEP does not have.
Some implementations of WPA also allow WEP clients to connect to the network, but security is then reduced to WEP level for all connected devices.
WPA includes support for remote authentication dial-in user service servers. In this setup, the server has access to device credentials, allowing users to authenticate themselves before connecting to the network. The server also includes extensible authentication protocol messages.