A Beginner's Guide to Authentication and Authorization

When you use any app or website, two security steps silently protect you: Authentication and Authorization.
Although the words sound similar, they serve different purposes in keeping your data secure.

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1. Simple Terms with Examples 📝

• Authentication → Prove who you are.
  Example: Entering your username & password to log into your email.

• Authorization → Decide what you can do once you’re in.
  Example: After logging in, you can read your emails but not someone else’s account.

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2. Professional View 💼

• Authentication: Verifying a user’s identity with credentials like passwords, biometrics, or tokens.
  Common methods: Passwords, Multi-factor Authentication (MFA), fingerprints, or face recognition.

• Authorization: Granting permissions to access certain resources or perform specific actions, usually based on roles or privileges.
  Common methods: Role-Based Access Control (RBAC), OAuth 2.0 scopes, access tokens.

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3. Authentication vs Authorization — Quick Table ⚖️

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4. Flow of Authentication & Authorization 🔄

1. User Submits Credentials: Username & password entered.

2. Authentication: System verifies the credentials.

3. ID Token Issued: Confirms your identity.

4. Authorization Check: System determines allowed resources/actions.

5. Access Token Issued: Contains permission details.

6. Access Granted or Denied: You can proceed or are blocked.

7. Ongoing Checks: For secure sessions, authorization may be re-verified.

   

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Final Thoughts 💡

• Authentication answers “Who are you?”

• Authorization answers “What can you do?”

They work together to secure your data but are not the same thing.

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