Abstract: A method of creating an electronic transaction record between a customer and a merchant is presented. The method entails generating a digital payment certificate that includes the customer's biometric authentication token that is associated with a time of payment instruction from the customer to use a payment method, and generating a digital receipt signed with the digital payment certificate after executing the payment instruction using the payment method. A database of customer's biometric data and associated payment methods is maintained. If a customer's biometric authentication token does not match the stored biometric data for the payment method in the payment instruction, the payment is rejected. The method and system not only prevents fraud, it also provides a validated record of payment.

Abstract: A portable interface device for extending the secure functionality of a computing device includes a plurality of ports and a controller, the ports being configured to facilitate communication between the interface device and one or more computing devices and between the interface device and one or more extension devices. The interface device extends the functionality of one or more computing devices by communicating to the computing device the functionality of one or more extension devices. Extension devices can be chained, and the interface device can emulate the combined functionality of the chained extension devices. A method for extending the functionality of a computing device detects an extension device for the computing device, identifies a functionality of the extension device, and communicates the functionality of the extension device to the computing device.