Multi-Factor Authentication (MFA) definition in Cybersecurity

Multi-Factor Authentication (MFA) is a security mechanism that requires users to provide two or more verification factors to gain access to a resource, such as an application, online account, or a VPN. MFA increases security by combining two or more independent credentials: what the user knows (password), what the user has (security token), and what the user is (biometric verification).

Open source or Free solutions

1. Google Authenticator
2. FreeOTP

Paying solutions

1. Duo Security
2. RSA SecurID