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 attacks.
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.
Note that if configured in Enterprise mode, which provides authentication using a RADIUS authentication server, it might require more power machines to crack...
