OAuth

OAuth is an open standard authorization protocol that allows third-party applications to access user data from online services without the need to store user credentials.

 

 

What is OAuth?

OAuth (Open Authorization) is an open protocol that enables secure delegation of access rights between different online services. It allows one application to access specific data from another service without requiring the user to share their password. Instead, the user authorizes one service to access certain resources from another platform, maintaining control over what is shared and for how long.

 

How OAuth appears in practice?

Real-world examples:

  • Sign-in with Google or Facebook – users authenticate through an existing account instead of creating new login credentials.
  • Calendar apps accessing Google Calendar – without storing or asking for user passwords.
  • Email tools pulling contacts from Outlook – OAuth allows secure, limited access.
  • Business app linking employee accounts to cloud storage – access is granted securely, without exposing login data.

 

In all these cases, OAuth ensures limited, controlled, and revocable access, which improves security and user experience.

 

How is OAuth different from similar terms?

  • OAuth vs. SSO (Single Sign-On):
    • OAuth umožňuje přístup ke konkrétním datům mezi službami.
    • SSO umožňuje přístup k více službám s jedním přihlášením.
  • OAuth vs. OpenID Connect:
    • OAuth slouží pro autorizaci (přístup k datům).
    • OpenID Connect je nadstavba OAuth pro autentizaci (ověření totožnosti).

 

Why this distinction matters:
OAuth is not a login system in itself—it’s a permission management framework. Misunderstanding this can lead to insecure implementation and overexposed user data.

 

How to implement or review OAuth in your company

Recommended steps:

  1. Map services in your environment that use OAuth.
  2. Ensure authorization flows through official, trusted providers (e.g., Google, Microsoft).
  3. Apply the least privilege principle – only grant access to necessary data.
  4. Monitor and audit access regularly – revoke unused or excessive tokens.
  5. Train employees to understand what it means to grant access via OAuth.

 

Why It Matters
OAuth is a powerful and secure standard—but only if implemented correctly. Many organizations unknowingly grant third-party apps excessive access. Even when passwords are safe, poorly configured permissions can lead to data leaks or compliance issues. Proper use of OAuth boosts trust, security, and usability in digital environments.

back to glossary