Ever logged in to an app with your Google or Facebook account? That frictionless login process is made possible by protocols such as OAuth 2.0 and OpenID Connect, but they’re not the same. Getting them mixed up could result in some serious security or functionality problems in your app. If you’re designing secure, scalable auth and authorization systems, understanding the difference between OAuth2 and 

OpenID Connect isn’t a nicety—it’s a necessity.”

The current digital environment demands securing the identities of users and controlling access to resources, and it should be of the utmost importance. Two commonly used protocols that solve these issues are OpenID Connect (OIDC) and OAuth 2.0. Although commonly referred to together, they are used for different purposes, and it is important to know their differences to implement the correct solution in your applications.

What is OpenID?

OpenID is an open standard and decentralized authentication protocol that lets users authenticate on several websites with one set of credentials from an identity provider (IDP). It saves users the hassle of remembering several usernames and passwords, making the login process easier. OpenID was developed to serve as a universal logon system, allowing users to gain access to various services without registering a new account for every service.

What is OAuth? Bonus

OAuth, short for Open Authorization, is an open authorization standard. It enables third-party applications to use a user’s resources without revealing their credentials. OAuth provides a way for users to grant applications a certain level of access to their information on other services, for example, enabling a picture editing application to access a user’s pictures on a cloud storage service. OAuth 1.0 was the original, but it has now been replaced by OAuth 2.0, which is more secure and flexible.

What is OAuth 2.0?

OAuth 2.0 is the second release of the OAuth protocol, developed to overcome the shortcomings of OAuth 1.0. OAuth 2.0 is a more secure and flexible authorization framework. OAuth 2.0 enables applications to get restricted access to user resources without revealing user credentials. 

It supports various grant types, such as authorization code, implicit, client credentials, and resource owner password credentials, to accommodate different use cases. OAuth 2.0 is widely adopted and serves as the foundation for many modern authentication and authorization systems.

Is OAuth 2.0 More Secure?

Yes, OAuth 2.0 is more secure than its older versions of OAuth. It brought with it some improvements such as improved methods of handling the access tokens, which lower the possibility of leakage of sensitive information. OAuth 2.0 operates using short lived tokens which expire after some time, so even if the token is copied by someone, it is safer. 

It also permits developers to declare scopes, which designate precisely what type of access the application has rights to. This will prevent apps from accessing more data than they need.By proper implementation of OAuth 2.0 is crucial. If not configured cautiously, threats may still emerge, so security best practices should be adhered to for its secure implementation.

Is OpenID Connect Better Than OAuth2?

OpenID Connect is not necessarily “better” than OAuth 2.0 and extends on OAuth 2.0 to include identity verification. OAuth 2.0 is utilized for authorization, but OpenID Connect includes authentication, meaning it verifies who the person is. 

If your app requires both authentication and authorization (such as logging in users and retrieving data about them), OpenID Connect is the way to go. If you simply need to manage the user’s access to resources, then OAuth 2.0 by itself is sufficient. OpenID Connect is a better choice when you want to authenticate the user’s identity, whereas OAuth 2.0 suffices if you simply wish to manage what resources the user can access.

Top Considerations: OAuth vs OpenID

OAuth and OpenID share many similarities when it comes to digital identity, but they differ in some ways. Using OpenID, you can connect to relying parties with only one sign-on, while OAuth grants apps access tokens. 

They both simplify, streamline, and secure authentication. Despite their similarities, they’re as different as night and day behind the scenes. The purpose of OpenID is to log you in, but the purpose of OAuth is to let apps access your data. 

OpenID: Focuses on authentication, verifying the user’s identity.

OAuth: Handles authorization, granting access to resources.

See this table for quick judgment.

Source- Geeks for geeks

In situations where users must be authenticated and their identity checked, OpenID is the preferred option. Nonetheless, if you aim to grant third-party applications access to users’ data without revealing credentials, OAuth works better. While most contemporary applications call for both authentication and authorization, which has seen the use of OpenID Connect.

What is OpenID Connect (OIDC)?

OpenID Connect (OIDC) is an authentication protocol that is based on OAuth 2.0. It integrates the authentication features of OpenID with OAuth 2.0’s authorization features, creating a complete solution for controlling user identity and access.

OIDC brings in the idea of ID tokens, which are JSON Web Tokens (JWTs) with user identity data, including the user’s name and email address. These tokens enable applications to authenticate a user and retrieve basic profile information. OIDC also specifies standard endpoints and scopes, like /authorize, /token, and openid, to make authentication easier.

By taking advantage of OAuth 2.0’s authentication framework, OIDC provides single sign-on (SSO) functionality, where users can sign in once and access several apps without having to re-enter their credentials. This improves user experience and security through password fatigue reduction and less vulnerability to credential stealing.

What to choose between OpenID, OAuth, or OpenID Connect (OIDC)

As the right protocol to use depends on your application’s needs, the choice between OpenID, OAuth, and OpenID Connect (OIDC) depends entirely on what your application needs to accomplish: authenticating users, granting resource access, or both.

A clear, structured answer is as follows:

Select OpenID (Legacy).

Purpose: Only for authentication

Use Case: Allow users to sign in to various websites using a single identity

Status: Mostly deprecated and superseded by OpenID Connect

Use only if you are working with legacy systems or integrating with older services that continue to support them.

Don’t use to new projects — use OIDC instead.

Select OAuth 2.0

Purpose: Only authorized (not authentication)

Use Case: Allowing applications to access user resources (such as calendars, contacts) without being able to view user passwords

• Apply when you have authorized third-party apps to act on your behalf
• Don’t use it when you have to authenticate a user’s identity (login).

Use: A fitness app that uploads workout data to Google Drive.

Next steps,

Understanding the distinctions between OpenID, OAuth, and OpenID Connect is crucial for implementing secure and efficient authentication and authorization mechanisms in your applications. While OpenID focuses on user authentication and OAuth on authorization, OpenID Connect combines both, offering a robust solution for modern identity management needs. 

By carefully evaluating your application’s requirements and selecting the appropriate protocol, you can enhance security, improve user experience, and streamline access management.