aircrack is an 802.11 WEP and WPA-PSK keys cracking program that can recover keys once enough data packets have been captured. Aircrack-ng is the next generation of aircrack with lots of new features.

It implements the standard FMS attack along with some optimizations like KoreK attacks, thus making the attack much faster compared to other WEP cracking tools. In fact, aircrack is a set of tools for auditing wireless networks. 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 dictionnary 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 and airbase-ng
• Optimizations, other improvements and bug fixing