Individual authentication is
|“||the process of establishing an understood level of confidence that an identifier refers to a specific individual.||”|
Individual authentication happens in two phases: (1) an identification phase, during which an identifier to be authenticated is selected in some way (often the identifier selected is the one claimed by the individual), and (2) an authentication phase, during which the required level of confidence is established (often by challenging the individual to produce one or more authenticators supporting the claim that the selected identifier refers to the individual). In the information security literature, individual authentication is sometimes referred to as "user authentication." In the biometrics literature, individual authentication of an identifier claimed by the individual is often called "verification."