The process of proving an individual is a claimed identity. Authentication is the first element of the AAA services concept, which includes Authentication, Authorization, and Accounting. Authentication occurs after the initial step of identification (i.e. claiming an identity). Authentication is accomplished by providing one or more authentication factors-Type 1: something you know (e.g. password, PIN, or combination), Type 2: something you have (e.g. smart card, RSA SecureID FOB, or USB drive), and Type 3: something you are (e.g. biometrics-fingerprint, iris scan, retina scan, hand geometry, signature verification, voice recognition, and keystroke dynamics).