OAuth 2.0 and OpenID Connect in Cybersecurity - Full Explanation

Introduction

Imagine you want to use a new app but don't want to share your password with it. You need a way to let the app confirm who you are and what it can access without risking your password. OAuth 2.0 and OpenID Connect solve this problem by safely sharing access and identity information between apps.

Explanation

OAuth 2.0: Secure Access Delegation

OAuth 2.0 lets you give a third-party app permission to access your data on another service without sharing your password. It works by issuing tokens that represent this permission. These tokens allow the app to act on your behalf for specific tasks and time limits.

OAuth 2.0 safely shares access rights without exposing your password.

OpenID Connect: Confirming Identity

OpenID Connect builds on OAuth 2.0 by adding a way to verify who you are. It provides an ID token that apps can use to confirm your identity securely. This helps apps know exactly who is logging in, not just that they have permission.

OpenID Connect adds identity verification to OAuth 2.0's access delegation.

Roles in OAuth 2.0 and OpenID Connect

There are four main roles: the user who owns the data, the client app requesting access, the authorization server that grants tokens, and the resource server that holds the data. These roles work together to control and protect access.

Clear roles help manage secure access and identity sharing.

Tokens: Access and ID Tokens

OAuth 2.0 uses access tokens to allow apps to use your data. OpenID Connect adds ID tokens that prove your identity. Tokens are like digital passes with rules about what they allow and how long they last.

Tokens are the keys that control what apps can do and who you are.

Common Flows: Authorization Code Flow

The Authorization Code Flow is a common way apps get tokens. It involves redirecting you to log in on a trusted server, which then sends a code back to the app. The app exchanges this code for tokens, keeping your password safe.

Authorization Code Flow protects your password by handling login on trusted servers.

Real World Analogy

Imagine you want to let a friend pick up your mail without giving them your house keys. You give them a special permission slip that only lets them collect mail for a limited time. If they want to prove who they are, they show an ID card linked to that permission slip.

OAuth 2.0: Secure Access Delegation → Permission slip allowing friend to pick up mail without keys

OpenID Connect: Confirming Identity → Friend showing an ID card to prove who they are

Roles in OAuth 2.0 and OpenID Connect → You (data owner), friend (client app), post office (authorization server), mailbox (resource server)

Tokens: Access and ID Tokens → Permission slip (access token) and ID card (ID token)

Common Flows: Authorization Code Flow → Friend getting permission slip from post office after showing ID

Diagram

Diagram

┌───────────────┐       ┌─────────────────────┐       ┌───────────────┐
│     User      │       │  Authorization      │       │   Client App  │
│ (Resource     │──────▶│  Server             │◀──────│               │
│  Owner)       │       │ (Issues Tokens)     │       │ (Requests     │
└───────────────┘       └─────────────────────┘       │  Access)      │
        │                        ▲                      └───────────────┘
        │                        │                             ▲
        │                        │                             │
        │                        │                             │
        │                        │                             │
        ▼                        │                             │
┌───────────────┐               │                             │
│ Resource      │◀──────────────┘                             │
│ Server        │                                             │
│ (Holds Data)  │─────────────────────────────────────────────┘
└───────────────┘

Diagram showing the interaction between User, Authorization Server, Client App, and Resource Server in OAuth 2.0 and OpenID Connect.

Key Facts

OAuth 2.0 → A protocol for granting limited access to user data without sharing passwords.

OpenID Connect → An identity layer on top of OAuth 2.0 that verifies user identity.

Access Token → A token that allows an app to access specific user data for a limited time.

ID Token → A token that confirms the user's identity to the app.

Authorization Code Flow → A secure process where apps get tokens by exchanging a code after user login.

Common Confusions

OAuth 2.0 and OpenID Connect are the same thing.

OAuth 2.0 and OpenID Connect are the same thing. OAuth 2.0 handles access permissions, while OpenID Connect adds identity verification on top of OAuth 2.0.

Access tokens contain user identity information.

Access tokens contain user identity information. Access tokens grant access rights but do not prove identity; ID tokens are used for identity confirmation.

Apps get user passwords during OAuth 2.0 login.

Apps get user passwords during OAuth 2.0 login. OAuth 2.0 uses redirects to trusted servers for login, so apps never see user passwords.

Summary

OAuth 2.0 lets apps access your data safely without sharing your password by using tokens.

OpenID Connect adds a way for apps to confirm who you are by providing identity tokens.

Clear roles and secure flows keep your data and identity protected during access and login.