A grey lock method to support once pre-freezing mechanism in IC card

Based on the traditional smart card grey lock method, the card can't be traded after grey lock. The paper put forward a new method to support once pre-freezing mechanism. The terminal can pre-freeze part of the money in card according to its actual situation, used to complete the corresponding business. User can take away the card after grey lock, and operate the balance in card except pre-freezing money, with loading, unloading, purchasing and so on financial transactions. It ensures that the card after grey lock can be finished a normal trading demand. So the method improves the convenience for using card.