What is the difference between authentication and authorization?

Question

Basic question from a novice:

What is the difference between authentication and authorization?

Answer 1

Authentication is the process of verifying who you are. Logging on to a PC with a username and password is authentication.

Authorization is the process of verifying that you have access to something. Gaining access to a resource (e.g. directory on a hard disk) because the permissions configured on it allow you access is authorization.

Answer 2

Authentication is about who somebody is.

Authorisation is about what they're allowed to do.

Answer 3

Authentication: I am an employee of the company. Here is my ID badge.

Authorization: As an employee of the company, I am allowed entrance into the building.

Answer 4

Authentication is the process of determining whether someone or something is, in fact, who or what it is declared to be. In private and public computer networks (including the Internet), authentication is commonly done through the use of logon passwords.
Authorization is the function of specifying access rights to resources, which is related to information security and computer security in general and to access control in particular.
For more information please see wikipedia