The use of two independent mechanisms to verify the identity of a user, such as a password and smart card or password and fingerprint scan. In these examples, people not only type in data but the smart card and fingerprint are unique physical objects that are difficult to duplicate.
Text a Security Code
Another common method is that after users log in with a password, a code is texted to their cellphone. Copying that security code from the phone into the login process provides the second authentication method. See authentication
, smart card
and one-time password