If the card operates in with rolling keys that change every session based on the UID and a master secret stored on the back-end server, recovery tools will only return gibberish. The data on the card is encrypted with a key that never touches the card reader.
The MIFARE protocol appends a parity bit to every byte transmitted. Due to a flaw in the Crypto1 filter function, these parity bits are generated using the internal state of the cipher before the keystream is applied, leaking critical information about the internal key state. mifare classic card recovery tool
