On December 27, 2013, Forbes reported that encrypted PIN data had been stolen in a data breach that occurred between black Friday and December 15th at Target stores. The data that was taken was from transactions associated with the check-out point-of-sale (POS) systems where debit cards are used by pay for purchase. Deit-card transactions require the customer to enter a PIN after they swipe their card at the point of sale. The encryption key that is used to encrypt the data is unique to the debit terminal and the debit processor. Encrypted data is absolutely worthless without the key.”]
Source: https://securityintelligence.com/target-hack-encrypted-pin-data-three-lessons/