• A A) An authentication mechanism in which a user enters a principal value during authentication.
  • B B) An entity that can be authenticated by a system by using the identifier associated with that entity.
  • C C) A person, computer, printer, device, or a group of these. For example, a person can be given a user ID as an identifier, which can then be used by a system to authenticate the user.
  • D B) and C)