entered in above steps 305 and 309 the first transaction validation code and the second transaction validation code can be calculated by using the symmetric cryptographic key as illustrated in fig4 in step 402 the card for transfer out firstly checks the internal state and if the check is passed then the step 403 is entered or else the transaction procedure is terminated in step 403 the card for transfer out records the first and the second transaction validation code in the transaction detail at last in step 404 the card for transfer out release the forbidding transfer out flag once the forbidding transfer out flag is released the card can continue to proceed the other transfer out transaction in above embodiments of the present invention instead of returning the validation signature for the card for transfer in after the card to card transfer initialization is executed the card for transfer out retains the validation signature for the card for transfer in until the transfer transaction has been completed thus this can ensure that the transaction is completed only on the condition that the card for transfer in is reliable and that the card for transfer out returns its signature for the transfer in party validation data in this way if the terminal repeatedly sends the data to the card for transfer in then because the signature can not be validated the.