OTP (One Time Password):-

          One Time Password (OTP) is also known as One Time Pin. It is a string of characters or numbers login session or transaction, on a computer system or other digital device. This prevents some forms of identity theft by making sure that a captured username/password pair cannot be used for the second time.

           It is a password that is valid for only one login session or transaction, on a computer system or other digital device. OTPs avoid a number of shortcomings that are associated with traditional (static) password-based authentication.