Aircrack-ng is a software suite specially designed for a wireless network and which operates under both the Windows and the Linux Operating System. Aircrack-ng consists of a packet sniffer, WPA cracker, and analysis tool and a detector for the wireless Local Area Networks (802.11). The best part of this software suit is one need not install it to use it. It is a collection of files which can be easily used with a command prompt.
