Aircrack-ng is a suite of wifi password cracking tools with 802.11 WEP and WPA-PSK protection.
The software also has other functions such as various types of attacks and tests.
It is also possible to capture data packets for future use with other applications.
The software was first developed for Linux but now there are versions for Windows, OS X, FreeBSD, OpenBSD, NetBSD, Solaris and eComStation 2.