Have you ever logged in to a website? What did you do? most of the time, first, you write down your username(maybe email) and then your password and finally click the login button to enter that website. That is the basic form of today’s websites. Most websites or any other systems need to authenticate users to know who they are and if he/she says I am Bob, he/she should prove it. but what if you cannot remember your username or password? You can read the full post on medium