What is the difference between authentication and Single Sign-On?
In computer security, authentication is the process by which a computer, computer program, or another user attempts to confirm that the computer, computer program, or user from whom the second party has received some communication is, or is not, the claimed first party. Single Sign-On is the subsequent automated authentication for additional systems after the user has logged on once. In this case, the authenticating system passes the user information to the subsequently called system. This is done in the background; that is, the user does not need to authenticate himself or herself again after his or her first logon.
