Which authentication method is closely associated with Microsoft applications?

WS-Federation is closely associated with Microsoft applications because it was designed specifically to work within the Microsoft ecosystem. This protocol allows for single sign-on (SSO) capabilities and enables identity federation between different security realms.

WS-Federation operates primarily on the principle of using claims-based authentication, which was a focus for Microsoft when developing its identity solutions, particularly with products such as Active Directory Federation Services (AD FS). These services enable organizations to extend the identities of users across organizational boundaries and across different applications, especially those developed by Microsoft.

The other authentication methods mentioned also serve important roles in identity management and federated authentication, but they may not be as tightly coupled with Microsoft applications or technologies. OAuth 2.0 and OpenID Connect are more widely recognized for their use in web applications and APIs but are not exclusive to Microsoft. SAML, while also used by Microsoft, is a more generic standard that is broadly adopted across different platforms. Thus, WS-Federation remains the most closely associated authentication method with Microsoft applications.