Fingerprint Matching: In this simplified diagram, the matching process consists of minutiae extraction followed by alignment and determination of corresponding minutiae stored as a template in the card’s flash memory. Even prints from the same finger won’t ever exactly match, because of dirt, sweat, smudging, or placement on the sensor. Therefore, the system has a threshold parameter: a maximum number of mismatched minutiae that a scanned fingerprint can have, beyond which the card will reject the print as inauthentic. In the case shown, just three minutiae don’t match up, and the user is positively authenticated.