Authentication to access a computer system requires at least one of three factors: something you know like a password or PIN; something you possess like an ATM, smart, or security token; or something you are through biometric identification using fingerprints, iris scans, facial recognition, or hand geometry. Common methods include entering a password or PIN, using a smart card or security token, and providing biometric data to a fingerprint, iris, or facial recognition reader. A security token dynamically generates and displays changing passwords as an additional authentication method.