What are WPA / WPA2?

Wi-Fi Protected Access (WPA and WPA2) is a class of systems to secure Wi-Fi networks. They are designed to replace the deficient older Wired Equivalent Privacy (WEP) standard.

WPA implements the majority of the IEEE 802.11i standard, and was intended as an interim measure while 802.11i was being prepared.

WPA is designed for use with an IEEE 802.1X authentication server, which distributes different keys to each user. Data encryption is done through the RC4 stream cipher, with a 128-bit key and a 48-bit initialization vector (IV). Temporal Key Integrity Protocol (TKIP) is used to change the keys dynamically. Besides, a more secure message integrity code (Michael) is used for better authentication.

WPA is designed to work with all wireless network interface cards, but not necessarily with first generation wireless access points.

WPA2 implements the mandatory elements of 802.11i. In addition to TKIP and the Michael algorithm, it introduces a new AES-based algorithm, CCMP, that is considered fully secure.

Note that WPA2 may not work with some older network cards.