Wi-Fi Protected Access (WPA) and Wi-Fi Protected Access 2 (WPA2) are wireless security protocols that were intended to address the security shortcomings of WEP. Because the WPA protocols dynamically generate a new key for each packet, they prevent the statistical analysis that caused WEP to fail. Nevertheless, they are vulnerable to some attack techniques as well.

WPA and WPA2 are frequently deployed with a pre-shared key (PSK) to secure communications between the access point and the wireless clients. The PSK should be a random passphrase of at least 13 characters in length; if not, it is possible to determine the PSK using a brute-force attack by comparing the PSK to a known dictionary. This is the most common attack.