The answer is the KMS key policy does not grant John the kms:Decrypt permission. This is the most likely cause because KMS uses a two-layer authorization model: the key policy acts as the primary access control for the KMS key itself, and IAM permissions alone are insufficient if the key policy explicitly denies or omits the decrypt action. Even with full administrator privileges in IAM, the key policy must explicitly allow the user to perform kms:Decrypt on that specific key; otherwise, the request fails with an AccessDenied error. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of the KMS key policy vs IAM permissions for decrypt, a common trap where candidates assume IAM admin rights override key policies. Remember, the key policy is the gatekeeper—IAM permissions can only grant access if the key policy already allows it. Memory tip: "Key policy first, IAM second—if the key says no, IAM can't say yes."
SCS-C02 Data Protection Practice Question
This SCS-C02 practice question tests your understanding of data protection. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Network Topology
Refer to the exhibit. A user named John encrypts a file using the AWS CLI. John then tries to decrypt the file but receives an AccessDenied error. John has full administrator permissions in IAM. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The KMS key policy does not grant John the kms:Decrypt permission.
Option B is correct because the key policy controls access to the KMS key. Even with full admin permissions in IAM, if the key policy does not grant the user decrypt permission, the request fails. Option A is wrong because the ciphertext is not malformed; the encryption succeeded. Option C is wrong because IAM permissions are not enough; key policy must allow. Option D is wrong because the error is about decrypt, not about key existence.
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.
✗
The ciphertext blob is malformed because it was not base64-decoded before decryption.
Why it's wrong here
The CLI handles base64 encoding; the error is access denied.
✗
John's IAM policy denies the kms:Decrypt action.
Why it's wrong here
John has full admin permissions; the issue is key policy.
✓
The KMS key policy does not grant John the kms:Decrypt permission.
Why this is correct
Key policy must explicitly allow decrypt for the user.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The key ID used for encryption is different from the key used for decryption.
Why it's wrong here
The error mentions the same key ID in the resource.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Data Protection — This question tests Data Protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The KMS key policy does not grant John the kms:Decrypt permission. — Option B is correct because the key policy controls access to the KMS key. Even with full admin permissions in IAM, if the key policy does not grant the user decrypt permission, the request fails. Option A is wrong because the ciphertext is not malformed; the encryption succeeded. Option C is wrong because IAM permissions are not enough; key policy must allow. Option D is wrong because the error is about decrypt, not about key existence.
What should I do if I get this SCS-C02 question wrong?
Identify which SCS-C02 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A security engineer is reviewing a KMS key policy. What does this policy accomplish?
medium
✓ A.Allow the SecurityAudit role to decrypt and re-encrypt data only from the same AWS account
B.Deny decryption to the SecurityAudit role
C.Allow the SecurityAudit role to use the key only for specific KMS keys
D.Allow any user from account 123456789012 to use the key
Why A: Option B is correct because the policy allows the SecurityAudit role to decrypt and re-encrypt only from the same account. Option A is wrong because it does allow decrypt and re-encrypt. Option C is wrong because the condition restricts to the same account. Option D is wrong because the policy doesn't restrict key usage to specific resources.
Last reviewed: Jun 20, 2026
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This SCS-C02 practice question is part of Courseiva's free Amazon Web Services 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 SCS-C02 exam.
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