What open-source solution offers SSO capabilities utilizing SAML?

Shibboleth is an open-source solution that provides single sign-on (SSO) capabilities through the implementation of the Security Assertion Markup Language (SAML). SAML is an open standard that allows organizations to exchange authentication and authorization data between identity providers and service providers. Shibboleth leverages this protocol to enable secure, seamless access to multiple applications and web resources using a single set of credentials.

With its robust support for federated identity management, Shibboleth facilitates user authentication across various domains without requiring users to log in separately to each service. This streamlines the user experience, enhances security by minimizing the number of credentials that need to be managed, and helps organizations maintain control over user access.

The other options, while they serve functionalities related to authentication and security, do not specifically provide SSO capabilities utilizing SAML in the same way that Shibboleth does. For example, Protected EAP is a protocol for securing wireless connections, OpenID is a decentralized authentication standard that does not rely on SAML, and Cross-Certification refers to the practice of allowing different public key infrastructure (PKI) systems to interact, rather than an SSO solution.