This AZ-204 practice question tests your understanding of implement azure security. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. A key principle to apply: pKCE protects public clients from authorization code interception attacks.. 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.
A single-page app signs in users with Microsoft Entra ID and calls a protected API. The app cannot safely keep a client secret. Which OAuth flow should be used? The team wants the control to be enforceable during normal operations.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Authorization code flow with PKCE
The authorization code flow with PKCE (Proof Key for Code Exchange) is the recommended OAuth flow for single-page apps because it prevents the client secret from being exposed by using a dynamically generated code verifier and challenge. This flow ensures that even if the authorization code is intercepted, it cannot be exchanged for tokens without the original code verifier, making it secure for public clients that cannot safely store secrets.
Key principle: PKCE protects public clients from authorization code interception attacks.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Implicit flow
Why it's wrong here
Implicit flow is legacy and less secure than authorization code with PKCE.
✗
Client credentials flow
Why it's wrong here
Client credentials is for daemon/service-to-service access, not user sign-in in a SPA.
✗
Resource owner password credentials flow
Why it's wrong here
ROPC is discouraged and incompatible with many modern security controls.
✓
Authorization code flow with PKCE
Why this is correct
PKCE protects public clients that cannot store secrets and is recommended for SPAs.
Related concept
PKCE protects public clients from authorization code interception attacks.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse the deprecated implicit flow (Option A) with the authorization code flow with PKCE, mistakenly thinking the implicit flow is still acceptable for SPAs, but Microsoft and OAuth standards now mandate PKCE for all public clients.
Detailed technical explanation
How to think about this question
Under the hood, PKCE works by the client generating a cryptographically random code_verifier (a high-entropy string) and its SHA-256 hash as the code_challenge, which is sent with the authorization request. When the authorization code is exchanged for tokens, the client must send the original code_verifier, which the authorization server verifies against the stored code_challenge, ensuring that even if the authorization code is intercepted, it cannot be used without the verifier. In real-world scenarios, this flow is critical for single-page apps using MSAL.js 2.0+, as it mitigates authorization code interception attacks without requiring a client secret.
KKey Concepts to Remember
PKCE protects public clients from authorization code interception attacks.
SPAs use PKCE to securely obtain access tokens without a client secret.
The `code_verifier` is a random string generated by the client for each request.
The `code_challenge` is a hashed version of the `code_verifier` sent in the initial request.
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
PKCE protects public clients from authorization code interception attacks.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. PKCE protects public clients from authorization code interception attacks. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this AZ-204 question in full detail.
Review pKCE protects public clients from authorization code interception attacks., then practise related AZ-204 questions on the same topic to reinforce the concept.
Implement Azure security — This question tests Implement Azure security — PKCE protects public clients from authorization code interception attacks..
What is the correct answer to this question?
The correct answer is: Authorization code flow with PKCE — The authorization code flow with PKCE (Proof Key for Code Exchange) is the recommended OAuth flow for single-page apps because it prevents the client secret from being exposed by using a dynamically generated code verifier and challenge. This flow ensures that even if the authorization code is intercepted, it cannot be exchanged for tokens without the original code verifier, making it secure for public clients that cannot safely store secrets.
What should I do if I get this AZ-204 question wrong?
Review pKCE protects public clients from authorization code interception attacks., then practise related AZ-204 questions on the same topic to reinforce the concept.
What is the key concept behind this question?
PKCE protects public clients from authorization code interception attacks.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This AZ-204 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the AZ-204 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.