Authentication is basically the process to confirm that a person (or user) is who they say they are. There are three classic "factors" that can be used to confirm a users' identity:Read on for a discussion of each.
♦ Using something only the user knows
♦ Using something unique the user has
♦ Using something that only the user is
Sometimes it's good to go back to the basics and this article does a fine job.
If you get to the end of that one and wonder if there might be more factors, you might want to check this one out: Four Factor Authentication.
