A method of how a user can prove his/her identity to a system. It can be a password, a fingerprint, a face scan.
An authenticator is the means used to confirm the identity of a user, that is, to perform digital authentication. A person authenticates to a computer system or application by demonstrating that he or she has possession and control of an authenticator. In the simplest case, the authenticator is a common password.
Using the terminology of the NIST Digital Identity Guidelines, the party to be authenticated is called the claimant while the party verifying the identity of the claimant is called the verifier. When the claimant successfully demonstrates possession and control of one or more authenticators to the verifier through an established authentication protocol, the verifier is able to infer the claimant's identity.
