A lot of times, people use those words interchangeably, since they are performed at the same moment, but in reality, they are critically different concepts. We can define these three concepts as follows:

To bring this into the real world, let's take an easy example and analyze the various phases: a web login with the username and password.

Let's imagine you are logging into your OpenStack Dashboard. The username you put in the username field, is the identification part. In fact, you affirm to be yourself, and the system trusts you on this. However, to let you do anything, the system needs to authenticate you. To do so, it needs your password and will check whether the...