Authentication is the process of verifying a claimed identity. In perhaps the
earliest form of authentication, the person being authenticated – called the user in this
article – would present a password to the authority requiring authentication – called the
authenticator. If the user were able to present the correct password, he or she would be
authorized to gain access to something or to receive services. For some purposes, simple
password authentication can provide relatively strong security, but in order to do so,
certain assumptions must hold true:wÉÉ}87H