Which federation standard is an XML-based framework for authentication, entitlement, and attribute information of users in a cloud?

SAML (Security Assertion Markup Language) is the correct answer because it specifically provides a standard for exchanging authentication and authorization data between parties, particularly in scenarios involving cloud services. It enables the transfer of user identity and privilege information through XML-based assertions, allowing a user to authenticate once and gain access to various services without needing to log in multiple times. This capability is essential in a cloud environment where different services may be managed by different entities, facilitating seamless single sign-on (SSO) experiences.

SAML's structure supports various scenarios, including web browser single sign-on and identity provider to service provider interactions, making it a widely adopted standard for federated identity management in cloud computing applications. It ensures that identity and attribute assertions can be securely communicated, allowing organizations to leverage federated identity solutions effectively.