Multi-factor access control is a security measure that requires users to provide two or more forms of authentication to gain access to a resource. The different factors that are used for authentication may include something that the user knows (such as a password), something that the user possesses (such as a token or smart card), or something that is unique to the user (such as biometric data).
When a user attempts to access a resource that is protected by multi-factor access control, they will typically be prompted to provide their credentials in two or more different ways. For example, they may be asked to enter their username and password, and then provide a fingerprint scan or insert a physical token into a card reader.
The system will then compare the credentials provided against a database of authorized users, and if both factors are verified, the user will be granted access to the resource. If either of the factors fails to authenticate, the user will be denied access.
The use of multiple factors significantly enhances the security of access control systems, as it makes it much more difficult for unauthorized users to gain access to sensitive resources. Even if a password is compromised, for example, an attacker would still need to provide another form of authentication to access the resource.
