Aircrack-ng is an 802.11 WEP and WPA-PSK keys cracking program that can recover keys once enough data packets have been captured. It implements the standard FMS attack along with some optimizations like KoreK attacks, as well as the all-new PTW attack, thus making the attack much faster compared to other WEP cracking tools. Aircrack-ng is a set of tools for auditing wireless networks – not for WiFi hacking.  Make sure you use this on your own network or one where you have permission to test.

Aircrack-ng is the next generation of aircrack with lots of new features:

• Better documentation (wiki, manpages) and support (Forum, trac, IRC: #aircrack-ng on Freenode).

  More cards/drivers supported

• More OS and platforms supported
• New WEP attack: PTW
• WEP dictionary attack
• Fragmentation attack
• Improved cracking speed
• Capture with multiple cards
• New tools: airtun-ng, packetforge-ng (improved arpforge), wesside-ng, easside-ng, airserv-ng, airolib-ng, airdriver-ng, airbase-ng, tkiptun-ng and airdecloak-ng
• Optimizations, other improvements and bug fixing