What is Multi-Factor Authentication?
Multi-factor authentication is a security method requiring a multiple layers of authentication for an individual to gain access to a system. Typically when you log-on to a network or service you enter your login credentials such as a username and a password. That would be considered the first layer. A multi-factor authentication system would require an additional layer of authentication. Other methods used for authentication can be broken down to these factors. Knowledge Factors (What you know ), Possession Factors (What you have), Inherence Factors (Biometrics), Location Factor (Where you are), and Time Factors.
Typical methods often used are hardware tokens. These are typical any hardware device that can be outfitted with a small chip.
Mobile Authentication tokens are sms messages or phone calls
Biometric Authentication such as a fingerprint scanner or facial recognition etc..