I’m working on a student portal mobile app that uses Google login. After users authenticate with their Google accounts, I need to send their OIDC ID token to our university backend system to get access to specific Drive folders.
My current implementation approach:
Mobile app does Google OAuth with OIDC to get ID token
App forwards this ID token to our university API endpoint
Backend validates the token using Google’s JWKS public keys
Server looks up the student’s assigned folder URL and returns it
Mobile app uses its own access token to call Drive API for that folder
Main questions I have:
Is it safe to pass ID tokens from client to server like this?
What’s the proper way to verify these tokens on the backend (signature checks, claims validation, etc)?
Should I also validate the token on mobile before sending, or just let the server handle it?
Any better patterns for this kind of user-specific folder access?
Additional details:
The mobile app and university server use different Google OAuth client IDs
Mobile app has separate Drive API access token
We handle sensitive academic data so security is really important
Any guidance on security best practices or alternative approaches would be helpful. Thanks!
totally agree! sending id tokens to the backend is pretty common. just make sure to double-check that the audience claim is your backend’s client id and that it’s issued by google. there’s no need to validate on mobile, your server should manage that.
You’re securely integrating Google login (OIDC) into your student portal mobile app to access specific Drive folders on your university’s backend. You’re concerned about the security of passing the OIDC ID token from the client (mobile app) to the server, and you want to ensure proper backend token validation and overall best practices for this architecture. You’re also using different Google OAuth client IDs for the mobile app and the university server, and you have a separate Drive API access token for the mobile app.
Understanding the “Why” (The Root Cause):
Directly passing the raw OIDC ID token from your mobile app to the backend introduces a security risk, albeit a manageable one if done correctly. The risk lies in the potential for an attacker to intercept the token during transit if the communication channel isn’t sufficiently secure (HTTPS is crucial here). A more secure approach involves minimizing the token’s lifespan and limiting its access. The backend should be the sole validator of the ID token. Client-side validation offers limited security benefits in this context, adding complexity without significantly mitigating the risks.
Step-by-Step Guide:
Secure Token Exchange: Instead of forwarding the raw ID token, have your mobile app immediately exchange it for a short-lived session token or a JSON Web Token (JWT) that your backend system issues. This minimizes the window of vulnerability. The mobile app sends this new token (issued by your server) to the backend for subsequent requests. This new token should be tied to a specific session and have an expiration time significantly shorter than the OIDC ID token’s lifetime.
Robust Backend Validation: On the backend, verify the OIDC ID token using Google’s JWKS (JSON Web Key Set) public keys. This involves:
Signature Verification: Ensure the token’s signature is valid using the corresponding public key.
Issuer Verification: Verify that the iss (issuer) claim matches a Google-authorized issuer (e.g., https://accounts.google.com).
Audience Verification: Ensure the aud (audience) claim matches your backend server’s client ID. This is crucial when using different client IDs for the mobile app and the backend. Your backend’s Google Cloud project needs to be configured to accept tokens from your mobile app’s client ID.
Expiration Time Verification (exp claim): Check that the token hasn’t expired.
Other Claim Validations: Depending on your security requirements, you may also need to verify other claims, such as the user’s email address or other profile information.
Backend Proxy for Drive API: Instead of directly returning folder URLs to the mobile app, your backend should act as a proxy for Drive API calls. The mobile app sends its session token to the backend, and the backend authenticates with the Drive API using its own credentials (service account or OAuth 2.0 credentials). This adds another layer of security, preventing the mobile app from directly interacting with the Drive API with potentially unnecessary permissions. The backend retrieves and processes the data before sending a controlled response to the mobile app.
Caching: Implement proper token caching on the backend to avoid repeatedly hitting Google’s JWKS endpoint. This improves performance and resilience.
Error Handling and Logging: Implement comprehensive error handling and logging for all stages of the authentication and Drive access flow. This aids in debugging and security monitoring.
Common Pitfalls & What to Check Next:
HTTPS: Ensure all communication between the mobile app and your backend is protected using HTTPS.
Client ID Configuration: Double-check the Google Cloud configuration to allow your backend’s client ID to accept tokens from your mobile app’s client ID.
Token Expiration: Monitor and manage session token expiration times carefully. Too short, and users will experience frequent re-authentication; too long, and you risk prolonged exposure of sensitive tokens.
Rate Limiting: Be mindful of Google’s API rate limits to avoid your application being throttled.
Security Audits: Conduct regular security audits of your application and API endpoints to ensure ongoing security.
Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!
Been there with OIDC setups - manual token validation is a nightmare. You’ll write endless boilerplate for JWKS verification, claim checks, and refresh logic.
Skip building that validation mess yourself. Automate it instead. Build a workflow that grabs incoming ID tokens, validates against Google’s endpoints, maps users to folder permissions, and spits out the right access credentials.
Best part? You handle edge cases automatically - expired tokens, permission changes, even adding new OAuth providers when your university inevitably wants more login options.
Seen teams waste weeks debugging OIDC validation when they could’ve automated everything in hours. You get logging and monitoring thrown in, so you know exactly what’s happening with each auth request.
For academic data, this is actually more secure since everything flows through one controlled layer instead of validation code scattered everywhere.
Check out https://latenode.com for this setup. Way cleaner than wrestling with JWKS endpoints manually.
Understanding the “Why” (The Root Cause):
Step-by-Step Guide:
Common Pitfalls & What to Check Next:
Still running into issues? Share your (sanitized) config files, the exact command you ran, and any other relevant details. The community is here to help!