OpenID is best described as which?

• A. An attestation model built upon XML for SOAP-based web services.
• B. An open standard decentralized protocol for authentication users.
• C. Utilizes a web of trust between organizations where they certify one another inside the federation.
• D. Provides authorization and specifies what access rights and privileges a user will have on a given system.

Answer: (B)

OpenID is an open standard decentralized protocol for authentication of users. It lets you sign in to many websites using an identity provider you trust, so the relying site can verify who you are without your having to create new credentials for each site. This focuses on proving identity (authentication) rather than granting access rights (authorization). The idea is that the site you’re signing into delegates the task of verifying your identity to a trusted provider, and then accepts that verification.

The other descriptions describe different concepts: an XML-based attestation model for SOAP-based web services refers to a distinct approach used in some enterprise or SOAP-based integrations; a web-of-trust federation describes broad, cross-organizational trust relationships rather than user-facing sign-in; and authorization deals with what actions or resources a user is allowed after logging in, not with proving who the user is.