What is authentification and authorization

Authentication is the mechanism whereby systems may securely identify their users. Authentication systems provide an answers to the questions: * Who is the user? * Is the user really who he/she represents himself to be? Authentication can be based on classical password, some physical property of the individual (fingerprint, retinal vascularization pattern, etc.), or some derived data (as in the case of so-called smartcard systems).
Authorization, by contrast, is the mechanism by which a system determines what level of access a particular authenticated user should have to secured resources controlled by the system. For example, a database management system might be designed so as to provide certain specified individuals with the ability to retrieve information from a database but not the ability to change data stored in the datbase, while giving other individuals the ability to change data.

Hi,

Great answer. I completely agree with it.

Authentication process: checking the users whether he/she is authorized for accessing the application or the function.

Authorization process: checking whether the user has the rights for a particular action or not.

Rubul Sarma

http://www.duke.edu/~rob/kerberos/authvauth.html

Authentication  : It is nothing but mainly it says about how the application has been made and what purpose it has been build 

Authorization means checking permission.
Authentication means checking credential.