The answer is that the KMS key is disabled, which is the most likely cause of the decrypt failure. When a customer master key (CMK) is disabled in AWS KMS, all cryptographic operations, including kms:Decrypt, are immediately blocked regardless of any IAM permissions or policies that explicitly allow the action. This scenario tests your understanding that KMS key state overrides IAM authorization—a disabled key cannot be used for any operation, even if the attached policy correctly grants kms:Decrypt and specifies the exact key ARN. On the AWS Certified Security Specialty SCS-C02 exam, this is a common trap where candidates focus only on IAM policy syntax and overlook the key’s operational status. A quick memory tip: think of the key state as a master switch—if the switch is off (disabled), no policy can turn the decrypt action back on.
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.
Refer to the exhibit. An administrator is investigating why an application that uses KMS for encryption is failing. The IAM role used by the application has the following policy attached: { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": "kms:Decrypt", "Resource": "arn:aws:kms:us-east-1:111122223333:key/1234abcd-12ab-34cd-56ef-1234567890ab" } ] }. What is the most likely cause of the failure?
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 is disabled
Option B is correct because the key is disabled, so decryption fails. Option A is wrong because the policy allows decrypt. Option C is wrong because the policy specifies the correct key ARN. Option D is wrong because the key exists.
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 KMS key has been deleted
Why it's wrong here
The key exists but is disabled.
✗
The IAM policy does not specify the correct key ARN
Why it's wrong here
The policy matches the key ARN shown.
✗
The IAM policy does not allow the kms:Decrypt action
Why it's wrong here
The policy explicitly allows kms:Decrypt.
✓
The KMS key is disabled
Why this is correct
A disabled key cannot be used for decryption.
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.
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.
Trap categories for this question
Command / output trap
The policy matches the key ARN shown.
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 company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
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 is disabled — Option B is correct because the key is disabled, so decryption fails. Option A is wrong because the policy allows decrypt. Option C is wrong because the policy specifies the correct key ARN. Option D is wrong because the key exists.
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.
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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.
Question Discussion
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