
Aircrack-ng
Aircrack-ng is a tool stash to screen, break down and test remote organizations around you. Check how secure your remote secret word is or open your neighbor's remote organization. It is able to decipher passwords for WPA (Wi-Fi Protected Access) and WEP (Wired Equivalent Privacy).
When you run the program, you'll have the option to catch information bundles for a particular organization because of one of the devices in the bundle: Airodump, a sniffer that gathers information bundles so you can test them later. Simply upload enough packets to Aircrack, and it will decrypt them and reveal the wireless network's password so you can access it.