OAuth is an open standard for access delegation, commonly used to grant websites or applications access to information on other websites but without giving them the passwords.
This is achieved through a process where users grant third-party access to specific types of information stored on another service, usually by authorizing through a token-based mechanism.
OAuth is extensively used in various applications for streamlining user authentication and authorization processes. For instance, when a user logs into a website using their Google or Facebook account, OAuth is at play. It enables users to share specific data with third-party websites or applications without exposing their full account details. This is particularly useful for services that require access to certain user data from another service, like accessing your contacts or calendar from a social media app. OAuth is also used in mobile app development, cloud services, and IoT devices where secure access to resources hosted by a third party is necessary. It simplifies the login process for users and enhances security by minimizing the spread of password-based login details.
As for its relationship with SAML (Security Assertion Markup Language) and OpenID: OAuth, SAML, and OpenID are all standards for authentication and authorization, but they serve different purposes.
SAML is primarily used for single sign-on (SSO) services to allow users to log in once and gain access to multiple systems without re-authenticating. It’s widely used in enterprise environments where multiple internal applications require secure access control.
On the other hand, OpenID is an authentication layer on top of OAuth, providing user identity verification. While OAuth focuses on granting access to resources without sharing the user’s credentials, OpenID allows the authentication of the user and provides basic profile information to the service provider.
OpenID Connect, an extension of OAuth, combines the best of both OAuth and OpenID, allowing for secure API authorization as well as user authentication.