OAuth2 vs sso: What are the differences?

Introduction

OAuth2 is an authorization framework that allows a user to grant third-party applications access to their resources without sharing their credentials, while Single Sign-On (SSO) is an authentication method that allows a user to use one set of credentials to access multiple systems.

1. Authentication vs Authorization: The key difference between OAuth2 and SSO lies in their primary focus. OAuth2 is primarily concerned with authorization, allowing third-party apps to access resources on behalf of a user. SSO, on the other hand, is focused on authentication, enabling users to authenticate once and access multiple systems without the need for multiple sets of credentials.
2. Granularity: OAuth2 provides a more fine-grained authorization approach compared to SSO. It allows users to control and grant specific permissions to individual third-party applications, ensuring that each app only has access to the necessary resources. SSO, on the other hand, typically provides a more general level of access, granting users access to multiple systems without distinction between different levels of authorization.
3. Multiple Applications: OAuth2 is designed to work seamlessly with various third-party applications, enabling users to access services from different providers using the same set of credentials. SSO, on the other hand, is typically implemented within a specific system or organization, providing a convenient way for users to access multiple applications within that particular environment.
4. Flexibility: OAuth2 offers greater flexibility compared to SSO. With OAuth2, users have the freedom to grant and revoke access to third-party apps as needed. They can easily manage the permissions and control which resources an app can access. SSO, on the other hand, may have more limited flexibility, often allowing users to access multiple applications within the specific SSO system but with less control over individual app permissions.
5. Security Scope: While both OAuth2 and SSO provide security benefits, their scope of security is different. OAuth2 primarily focuses on securing authorization and preventing unauthorized access to resources by third-party applications. SSO, on the other hand, focuses on securing authentication and reducing the risk of password-related vulnerabilities by centralizing the login process.
6. Implementation Complexity: The implementation complexity of OAuth2 and SSO differs. OAuth2 can be more complex to implement, especially for developers integrating third-party applications. It requires the use of specific protocols and the need to handle token management effectively. On the other hand, SSO implementation can also be complex but is often simplified within a specific system or organization, with pre-defined guidelines and protocols.

In summary, OAuth2 primarily focuses on authorization, provides fine-grained access control, works with multiple applications, offers flexibility in managing permissions, focuses on securing authorization, and can be complex to implement. SSO, on the other hand, focuses on authentication, provides general access control, is implemented within a specific system or organization, reduces password-related vulnerabilities, and is often simplified in implementation.