Originally published on Medium.
In the digital world, ensuring that a user is who they claim to be is crucial and ensuring secure access and interaction with applications is paramount. This requires understanding both authentication (verifying user identity) and authorization (granting access to resources). Today, we’ll explore key mechanisms in this landscape: Sessions, JWT (JSON Web Tokens), Token-based authentication, SSO (Single Sign-On), and OAuth 2.0, highlighting their roles in authentication and authorization.
1. Session-based Authentication (Authentication)
Session-based authentication is a traditional method where the server creates a session for the user after verifying their credentials (e.g., username and password). A session ID is then sent to the user’s browser, encapsulated in a cookie, marking the browser with a unique identifier for the duration of the session. This approach is straightforward but has limitations like the inability to fully control the login lifecycle and challenges in supporting mobile apps.
2. JWT (JSON Web Tokens) (Authentication/Authorization)
JWTs are a modern solution for secure communication between parties. A JWT is a compact token that consists of a header, a payload, and a signature. The server generates a JWT after authenticating the user and sends it to the client. The client then uses this token for subsequent requests. JWTs can serve both as an authentication mechanism (verifying the user’s identity) and an authorization tool (carrying claims about what resources the user is allowed to access).
3. Token-based Authentication (Authentication/Authorization)
Token-based authentication is a broad term that encompasses methods like JWT. It involves issuing a token (a small piece of data) to a user after successful authentication. This token is then used for authorizing future requests by the user, helping to manage sessions and access to resources. This method supports mobile applications effectively, overcoming the limitations of traditional session cookies.
4. SSO (Single Sign-On) (Authentication)
SSO is an authentication scheme that allows users to log in with a single ID and password to access a range of systems or applications. It’s primarily an authentication mechanism, streamlining the login process for users across multiple platforms. SSO systems often rely on a central authentication server that verifies user identities and then informs other applications about the user’s authenticated state.
5. OAuth 2.0 (Authorization)
OAuth 2.0 is a framework for authorization. It allows third-party applications to obtain limited access to an HTTP service, either on behalf of a resource owner by orchestrating an approval interaction between the resource owner and the HTTP service, or by allowing the third-party application to obtain access on its own behalf. This makes OAuth 2.0 strictly an authorization mechanism, differentiating it from authentication solutions like SSO.
6. Conclusion
The world of online security is complex, filled with different tools for keeping things safe and managing who gets access to what. By understanding how these tools — like session IDs, JWTs, tokens, single sign-on, and OAuth 2.0 — work, anyone making apps or websites can ensure they’re both easy to use and protected from unwanted access.