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).
Authentication (from Greek: αὐθεντικός authentikos, "real, genuine", from αὐθέντης authentes, "author") is the act of proving an assertion, such as the identity of a computer system user. In contrast with identification, the act of indicating a person or thing's identity, authentication is the process of verifying that identity. It might involve validating personal identity documents, verifying the authenticity of a website with a digital certificate, determining the age of an artifact by carbon dating, or ensuring that a product or document is not counterfeit.
