OpenID vs OAuth: A Simple Guide with Examples
Ensuring that users can safely log into your application is crucial in online security. Two popular protocols that help with this are OpenID and OAuth. While they often work together, they serve different purposes. Let’s break them down in simple terms and explore how they can be used with examples.
What is OpenID?
OpenID is a protocol that allows users to log into multiple websites using a single set of credentials. Think of it as your universal key to access different doors (websites) without needing a separate key.
Example of OpenID:
Imagine you have a Google account. With OpenID, you can use your Google credentials to log into other websites like StackOverflow or GitHub. This means you don’t need to create a new username and password for each site.
What is OAuth?
OAuth is a protocol designed for authorization. It allows one application to access resources (like data) from another application on behalf of the user. It’s like giving a valet key to a parking attendant — they can park your car without having access to everything inside.
Example of OAuth:
Suppose you are using a fitness app that wants to post your workout stats to your Facebook timeline. With OAuth, the fitness app can request permission to post on your behalf without needing your Facebook password.
Key Differences
Purpose:
- OpenID is primarily for authentication (logging in).
- OAuth is for authorization (granting access to resources).
Usage:
- OpenID is used when you want to log into a website using another service.
- OAuth is used when an application needs to access resources from another service on behalf of the user.
How They Work Together
Often, OpenID and OAuth are used together to provide a seamless experience. For instance, when you log into an application using your Google account, OpenID is used for authentication. If the application needs to access your Google Drive, OAuth comes into play for authorization.
Practical Example: Logging into an App Using Google
Let’s walk through a simple scenario:
- Authentication with OpenID:
- You visit an application (e.g., a new photo-sharing app).
- You choose to log in using your Google account.
- The app redirects you to Google’s login page.
- You enter your Google credentials.
- Google verifies your identity and sends an authentication token back to the app.
- You are now logged into the app without needing a new username and password.
2. Authorization with OAuth:
- While logged in, the app asks for permission to access your Google Photos to upload images directly.
- The app redirects you to Google’s authorization page.
- You see a prompt asking if you want to allow the app to access your photos.
- You grant permission.
- Google sends an access token to the app.
- The app can now upload photos to your Google Photos without needing your Google password.
Conclusion
Understanding the difference between OpenID and OAuth is important for designing secure and user-friendly applications. OpenID makes logging in easy, while OAuth ensures that apps can access resources securely on behalf of users. By combining these protocols, developers can create a seamless and secure user experience.
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