Which federated identity method, based on SAML, is commonly used by universities and public service organizations?

The correct choice highlights Shibboleth as a federated identity method that is especially well-suited for universities and public service organizations because it leverages the SAML protocol for identity management and single sign-on capabilities. Shibboleth enables seamless, secure sharing of identity information and access across different institutions and services, which is essential for educational environments where users often need to access resources from various platforms that may not directly share authentication data.

This method also supports a flexible attribute release policy, allowing organizations to control which user attributes (like name, email, and institutional affiliation) are shared and with whom. This feature is particularly important for universities that must maintain compliance with privacy regulations while facilitating user access to various educational and administrative services.

The other options, while related to the broader context of identity management and federated access, do not specifically embody the attributes or functionalities suited to the academic and public sectors that Shibboleth provides. For instance, OpenID is more commonly utilized for consumer web applications rather than complex academic environments requiring intricate integrations, while transitive trust is a concept rather than a specific federated identity method. SAML, on the other hand, is a protocol and not a method itself, and while it's a foundation for Shibboleth