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Multi Factor Authentication


How to make sure User A is User A as he claims, not User a.

Our old movies smugglers can teach us a few tricks here. There are multiple levels or factor of authentication.

1. First Factor - Something you only know. It's like a secret pin, key, pattern or password.
    In the old movie, there used to be a secret code between smugglers.  Parties involved in the transaction only knows this secret code.

2. Second Factor - Something you only own. It's like the ATM card, phone, device or OTP. 
    In the old movies, smugglers used torn currency note. Both parties will have one part.  One party need to show ownership of half of the torn currency note to receive goods from another party.

3.  Third Factor - Something you are. It's related to your physical appearance. Like your face, your thumb impression or voice. Your personal physical traits will be used to identify you.
     Remember hero duplicates being used to catch smugglers. These were negative applications of third factor tough. 

Above three or widely used in IT for now. There is 2 more factor of authentication mostly related to human behaviour. I am yet to find their real-life applications before I write them here.




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