The answer is SAML 2.0 and OpenID Connect (OIDC). These two protocols are the industry standards for identity federation because they enable secure, cross-domain single sign-on (SSO) by establishing trust between an identity provider (IdP) and a service provider (SP). SAML 2.0 uses XML-based assertions to exchange authentication and authorization data, making it a cornerstone of enterprise federation, while OIDC, built on OAuth 2.0, provides a lightweight, JSON-based identity layer that verifies end-user identity via ID tokens (JWTs). On the CISSP exam, this concept tests your understanding of federated identity management within Domain 2 (Asset Security) and Domain 4 (Communication and Network Security). A common trap is confusing OAuth 2.0 with OIDC—remember that OAuth 2.0 is an authorization framework, not an identity protocol, whereas OIDC adds the authentication layer. Memory tip: SAML is the “heavy XML” for enterprise, OIDC is the “light JSON” for modern web and mobile.
CISSP Identity and Access Management Practice Question
This CISSP practice question tests your understanding of identity and access management. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Which TWO protocols are commonly used for identity federation?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
OpenID Connect
OpenID Connect (OIDC) is an identity layer built on top of OAuth 2.0 that enables clients to verify the identity of an end-user based on the authentication performed by an authorization server. It provides a standardized way to obtain identity claims via an ID token (JWT) and is widely used for federated identity scenarios, such as single sign-on (SSO) across domains. SAML 2.0 is an XML-based protocol for exchanging authentication and authorization data between an identity provider (IdP) and a service provider (SP), making it a cornerstone of enterprise identity federation.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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LDAP
Why it's wrong here
LDAP is a directory access protocol, not a federation protocol.
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OAuth 2.0
Why it's wrong here
OAuth 2.0 is an authorization framework; it is used in federation but is not itself a federation protocol.
✓
OpenID Connect
Why this is correct
OpenID Connect is an identity layer on top of OAuth 2.0 for federated authentication.
Related concept
Read the scenario before looking for a memorised answer.
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RADIUS
Why it's wrong here
RADIUS is for AAA in network access, not federation.
✓
SAML 2.0
Why this is correct
SAML is widely used for exchanging authentication and authorization data between parties.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse OAuth 2.0 with OpenID Connect, mistakenly selecting OAuth 2.0 as a federation protocol when it is solely an authorization framework, not an identity protocol—OpenID Connect is the correct identity layer built on top of it.
Detailed technical explanation
How to think about this question
Under the hood, OpenID Connect uses a JSON Web Token (JWT) as the ID token, which contains claims like 'sub' (subject identifier), 'iss' (issuer), and 'aud' (audience), signed by the IdP to ensure integrity. SAML 2.0 relies on XML-based assertions (e.g., AuthnRequest and Response) that can be signed and encrypted, and it supports both IdP-initiated and SP-initiated SSO flows. A real-world scenario: an enterprise using SAML 2.0 to federate with a cloud SaaS provider (e.g., Salesforce) must manage metadata exchanges and certificate trust, while a consumer app using OpenID Connect (e.g., 'Sign in with Google') relies on OAuth 2.0 flows plus the ID token for user authentication.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A security analyst at a medium-sized enterprise encounters this scenario during an investigation or architecture review. The correct answer reflects best practice for the specific threat or control described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Security exam questions test whether you can match controls to threats in context — not just recall definitions.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Identity and Access Management — This question tests Identity and Access Management — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: OpenID Connect — OpenID Connect (OIDC) is an identity layer built on top of OAuth 2.0 that enables clients to verify the identity of an end-user based on the authentication performed by an authorization server. It provides a standardized way to obtain identity claims via an ID token (JWT) and is widely used for federated identity scenarios, such as single sign-on (SSO) across domains. SAML 2.0 is an XML-based protocol for exchanging authentication and authorization data between an identity provider (IdP) and a service provider (SP), making it a cornerstone of enterprise identity federation.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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