openid connect vs oauth

Answer from ChatGPT

OpenID and OAuth are related but distinct protocols that serve different purposes in the context of web authentication and authorization.

OAuth (Open Authorization): OAuth is an open standard for access delegation. It allows a user (resource owner) to grant a third-party application (client) limited access to their resources on a resource server (typically owned by a different party) without sharing their credentials (e.g., username and password) with the client. OAuth is commonly used for enabling Single Sign-On (SSO) across different applications and services.

OAuth provides a framework for granting access tokens that represent specific scopes or permissions to access certain resources. These tokens are then used by the client to access the protected resources on behalf of the user. The OAuth protocol includes various flows, such as Authorization Code Flow, Implicit Flow, and Client Credentials Flow, to accommodate different use cases.

OpenID Connect (OIDC): OpenID Connect is an extension of OAuth 2.0 and serves as an identity layer on top of OAuth. It adds the ability to authenticate users, not just authorize access to resources. In other words, while OAuth deals with resource access, OpenID Connect deals with user authentication and providing identity information.

OpenID Connect introduces additional endpoints and claims to identify and authenticate users. It allows clients to obtain identity information about the user, such as their name, email, and unique identifier (sub), in the form of ID tokens. ID tokens are JSON Web Tokens (JWTs) that contain information about the authenticated user.

In summary:

OAuth is primarily focused on access delegation and authorization, allowing third-party applications to access limited resources on behalf of the user without knowing the user's credentials.
OpenID Connect builds on top of OAuth and adds authentication capabilities, enabling clients to verify the identity of the end-user and obtain user information.

Together, OAuth and OpenID Connect form a powerful combination for secure and user-friendly authentication and authorization in modern web applications, providing mechanisms for both granting access to resources and verifying the identity of users.

Answer from Bard

OpenID Connect (OIDC) and OAuth 2.0 are both authorization frameworks, but they serve different purposes. OAuth 2.0 is used to authorize third-party applications to access protected resources. OIDC is used to authenticate users and obtain their profile information.

Here is a table that summarizes the key differences between OAuth 2.0 and OIDC:

Feature	OAuth 2.0	OIDC
Purpose	Authorize third-party applications to access protected resources	Authenticate users and obtain their profile information
Credentials	Client ID and client secret	Client ID and client secret, plus user's consent
Scopes	Permissions that the third-party application is requesting	Permissions that the third-party application is requesting, plus user's profile information
Tokens	Access tokens, refresh tokens, and authorization codes	ID tokens, access tokens, and refresh tokens
Use cases	Social login, API access, single sign-on	Social login, API access, single sign-on

Here is a table that summarizes the key differences between OAuth 2.0 and OIDC:

Feature	OAuth 2.0	OIDC
Purpose	Authorize third-party applications to access protected resources	Authenticate users and obtain their profile information
Credentials	Client ID and client secret	Client ID and client secret, plus user's consent
Scopes	Permissions that the third-party application is requesting	Permissions that the third-party application is requesting, plus user's profile information
Tokens	Access tokens, refresh tokens, and authorization codes	ID tokens, access tokens, and refresh tokens
Use cases	Social login, API access, single sign-on	Social login, API access, single sign-on

In general, OAuth 2.0 is a more flexible framework than OIDC. OAuth 2.0 can be used to authorize third-party applications to access a wide variety of protected resources. OIDC is more focused on authentication and obtaining user profile information.

Here are some examples of how OAuth 2.0 and OIDC can be used:

Social login: OAuth 2.0 can be used to allow users to log in to your application using their Facebook, Google, or Twitter accounts.
API access: OAuth 2.0 can be used to allow third-party applications to access your APIs.
Single sign-on: OAuth 2.0 can be used to allow users to sign in to multiple applications using a single set of credentials.
Authentication: OIDC can be used to authenticate users and obtain their profile information. This can be used to create a single sign-on experience for your users.
Profile information: OIDC can be used to obtain the user's profile information, such as their name, email address, and picture. This information can be used to personalize your application for the user.

Which framework you choose will depend on your specific needs. If you need a flexible framework that can be used for a variety of purposes, OAuth 2.0 is a good choice. If you need a framework that is specifically designed for authentication and obtaining user profile information, OIDC is a good choice.

OpenID Connect is an extension of OAuth 2.0. It adds a number of features to OAuth 2.0, such as:

User authentication: OIDC provides a way for the client to authenticate the user directly with the authorization server. This is done by using the Authorization Code Grant flow.
ID tokens: OIDC defines a new type of token called an ID token. The ID token contains the user's identity information, such as their name, email address, and picture. This information can be used to personalize the client's experience.
Userinfo endpoint: OIDC defines a new endpoint called the Userinfo endpoint. This endpoint can be used by the client to retrieve the user's profile information.

In addition to these features, OIDC also provides a number of other benefits, such as:

Standardized: OIDC is a standardized protocol, which means that it is supported by a wide range of identity providers and clients.
Secure: OIDC uses a number of security features to protect the user's identity and data.
Extensible: OIDC is extensible, which means that it can be customized to meet the specific needs of different applications.

Overall, OIDC is a more secure and feature-rich protocol than OAuth 2.0. However, it is also more complex. If you need a simple and flexible authorization framework, OAuth 2.0 is a good choice. If you need a more secure and feature-rich authorization framework, OIDC is a good choice.

Not all OAuth providers can be connected by OpenID Connect. OpenID Connect is an extension of OAuth 2.0, but it does not add any new flows. This means that an OAuth provider must support the Authorization Code Grant flow in order to be used with OpenID Connect.

There are a number of OAuth providers that do not support the Authorization Code Grant flow. These providers include:

Google OAuth
Facebook OAuth
Twitter OAuth

If you are using one of these OAuth providers, you will not be able to use OpenID Connect to authenticate users. You will need to use a different authentication method, such as username and password authentication.

Here are some of the OAuth providers that support the Authorization Code Grant flow and can be connected by OpenID Connect:

Microsoft Azure AD
Okta
Ping Identity
Auth0

If you are using one of these OAuth providers, you can use OpenID Connect to authenticate users. This will give you the benefits of OIDC, such as user authentication, ID tokens, and the Userinfo endpoint.