Abstract: A method of using a card which has a substrate with at least one magnetic track thereon, the method involving dividing the track into a plurality of spaced blocks with a start sentinel being magnetically recorded at the start of each block. A user's critical data is recorded in at least some of the blocks, this critical data including a portion of the user's personal identification number. The method further includes enhancing the security of a cash card by recording in variable locations on the cash card the last date when the user has had a transaction with a terminal, recording in scrambled locations on the card balance information plus security information and storing in a terminal a set of descrambling tables. The user introduces the card into the terminal and enters the user's personal identification number associated with the card.