The process of verifying identifying information to confirm that a user is who they claim to be. Authentication is performed using one of the following three methods:
Knowledge (What You Know): Whether the user knows a password or PIN that only the account owner would know.
Possession (What You Have): Whether the user possesses a smart card or token that only the account owner would have.
Inherence (What You Are): Whether characteristics such as fingerprint, voice, or retina match those of the account owner.