Original version of tool posted by @JMP-JECXZ but without "hardnested" attack:
MFOC is an open source implementation of "offline nested" attack by Nethemba.
This program allow to recover authentication keys from MIFARE Classic card.
Please note MFOC is able to recover keys from target only if it have a known key: default one (hardcoded in MFOC) or custom one (user provided using command line).
Code:
https://github.com/nfc-tools/mfoc
You can find a lot more interesting NFC tools here:
Code:
https://github.com/nfc-tools