10. Authentication

Authentication is the process of validating the identity of someone or something. It uses information provided to the authenticator to determine whether someone or something is, in fact, who or what it is declared to be. In private and public computing systems, for example, in computer networks, the process of authentication commonly involves someone, usually the user, using a password provided by the system administrator to logon. The user’s possession of a password is meant to guarantee that the user is authentic. It means that at some previous time, the user requested, from the system administrator, and the administrator assigned and or registered a self-selected password. The user presents this password to the logon to prove that he or she knows something no one else could know. Generally, authentication requires the presentation of credentials or items of value to really prove the claim of who one is. This chapter discusses this process of authentic proof of a system user.