Topic: MFOC - Mifare Classic Offline Cracker
Last year (2009), the Nethemba team have implemented and released their open source implementation of "offline nested" attack.
This tool allow to recover one or more keys from Mifare Classic very quickly (few minutes) if at least one key is known.
Thanks to Norbert Szetei and Pavol Luptak for their attack's implementation.
Thanks to Michal Boska for making this works with libnfc 1.3.3.