2 factor authentication
a system that requires at least two steps or more to unlock account; each step adds a new layer of security that uses something you have and something you got
Usernames and Passwords
a string of characters that allows access to a computer system or service
token-based authentication
Requires a computer user to physically hold a device called a token.
Biometrics
the identification of a user based on a physical characteristic, such as a fingerprint, iris, face, voice, or handwriting