ExpressPay is a stored-value cash card system which utilizes the Infineon SLE4442 chip; it was developed by enTrac Technologies of Toronto, Ontario, and its largest application is as the pre-paid cash card system in use at FedEx Kinko's. Analysis of a few dozen cards reveals that the data stored on the card is unencrypted and poorly protected against fraud, and a simple attack can be used to obtain the security code necessary to alter the data on the card. This talk will step the audience through the analysis, research, attack, and subsequent tests performed on the ExpressPay system, and conclude with recommendations on how to implement a more secure stored-value card system.