AWS Multi-Factor Authentication (AWS MFA) is an additional layer of security for accessing AWS services. When you enable this optional feature, you will need to provide a six-digit single-use code in addition to your standard user name and password credentials before access is granted to your AWS Account settings or AWS services and resources. You get this single-use code from an authentication device that you keep in your physical possession. This is called multi-factor authentication because more than one authentication factor is checked before access is granted: a password (something you know) and the precise code from your authentication device (something you have).