Auth0 uses OpenID Connect and OAuth 2.0 to authenticate users and verify their identity.

Authentication refers to the process of confirming identity. While often used interchangeably with authorization, authentication represents a fundamentally different function.

In authentication, a user or application proves they are who they say they are by providing valid credentials for verification. Authentication is often proved through a username and password, sometimes combined with other elements called factors, which fall into three categories: what you know, what you have, or what you are.

  • Single-Factor Authentication relies on a password. Example: a school website that only requires validating a password against a username.

  • Two-Factor Authentication relies on a piece of confidential information in addition to a username and password. Example: a banking website that validates a password against a username and then requires the user to enter a PIN known to only the user.

  • Multi-Factor Authentication (MFA) uses two or more security factors from independent categories. Example: a hospital system that requires a username and password, a security code received on the user's smartphone, and fingerprint.

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