Patent ID: 8240561

Claim:
A method of contactless smartcard authentication, comprising: detecting the presence of a contactless smartcard at a card reader; measuring an impulse response of the card reader to the presence of the contactless smartcard; and obtaining calibration data for the contactless smartcard, wherein the calibration data comprises at least one of a tolerance of the contactless smartcard to variations in pulse timing, a tolerance of the contactless smartcard to variations in pulse spacing, a tolerance of the contactless smartcard to variations in modulation depth, or a tolerance of the contactless smartcard to variations in the CSC protocol; determining at least one challenge for the contactless smartcard based on the calibration data; detecting a response of the contactless smartcard to the at least one challenge; and authenticating the contactless smartcard based on the measured impulse response of the card reader; wherein the contactless smartcard is authenticated based on a result of comparing the impulse responses and the response to the at least one challenge.