Two-Factor Authentification or 2FA is an extra layer of security while accessing service or a web app. To verify user’s identity, 2-Factor authentification requires both online password and mobile number. The users not just receive credentials of the service to access sensitive data but they also receive a one-time passcode or Pin number via SMS ot on their token. Users have their mobile phones with them all the time so the advantage of using mobiles for 2FA is obvious: user receive verification code on something only they have. The way it works is that the user has a one-time PIN number (OTP) sent to their mobile phone, then user just types the received OTP into application form to confirm the persona.