The process of validating user is called authentication.Usually we can implement authentication by using name and password combination.

It is the process of validating access permissions of the user i.e it is the process of checking whether the user is allowed to access a particular resource or not . After authentication we have to perform authorization.Usually we can Implement authorization by using access control list (ACL).

Data integrity

It is the process of ensuring that data should not be changed in transmission from to server. We can implement data integrity by using SSL (secure socket layer).

Example: It we are sending a request to transfer 1000rs from our account to another the server should get the request for 1000 but not for 10000.

Confidentiality(data privacy)
It is the process of ensuring that no-one except intended user is able under stand our information we can achieve this by using various encryption techniques.