The answer is to modify the KMS key policy to allow the specific IAM role to use the key for decryption, enforce SSE-KMS via a bucket policy, and grant kms:Decrypt to that role. This works because SSE-KMS uses a customer managed key to encrypt objects at rest, and controlling decryption requires explicitly limiting kms:Decrypt permissions in the key policy to only the designated IAM role, while the bucket policy enforces the encryption requirement by denying PutObject without the x-amz-server-side-encryption header set to aws:kms and the specific key ARN. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of the layered access control between S3 bucket policies and KMS key policies, with a common trap being to confuse SSE-S3 or client-side encryption as valid alternatives—they are not, because SSE-S3 lacks customer-managed key control and client-side encryption is not server-side. Remember the memory tip: “Bucket policy enforces the lock, key policy controls the key.”
SCS-C02 Data Protection Practice Question
This SCS-C02 practice question tests your understanding of data protection. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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.
A company is implementing a data protection strategy for its Amazon S3 bucket that contains sensitive data. The company requires that all objects be encrypted at rest using server-side encryption with a customer managed key (SSE-KMS). Additionally, the company wants to ensure that only a specific IAM role can decrypt objects. Which THREE actions should the company take?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Attach an IAM policy to the specific role that grants kms:Decrypt on the customer managed key
To enforce SSE-KMS, use a bucket policy that denies PutObject without the x-amz-server-side-encryption header set to aws:kms and a specific key. To control decryption, grant kms:Decrypt to the specific role. Option A, C, and D are correct. Option B is incorrect because using SSE-S3 does not meet the requirement. Option E is incorrect because client-side encryption is not S3 server-side encryption.
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.
✓
Attach an IAM policy to the specific role that grants kms:Decrypt on the customer managed key
Why this is correct
Allows decryption by that role.
Related concept
Read the scenario before looking for a memorised answer.
✓
Create a bucket policy that denies s3:PutObject unless the request includes the x-amz-server-side-encryption header with value aws:kms
Why this is correct
Enforces SSE-KMS on upload.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use the default S3-managed key (SSE-S3) for encryption
Why it's wrong here
Does not use customer managed key.
✓
Modify the KMS key policy to allow the specific IAM role to use the key for decryption
Why this is correct
Key policy grants decryption.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use client-side encryption with a customer managed key
Why it's wrong here
Client-side encryption is not server-side encryption.
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: Attach an IAM policy to the specific role that grants kms:Decrypt on the customer managed key — To enforce SSE-KMS, use a bucket policy that denies PutObject without the x-amz-server-side-encryption header set to aws:kms and a specific key. To control decryption, grant kms:Decrypt to the specific role. Option A, C, and D are correct. Option B is incorrect because using SSE-S3 does not meet the requirement. Option E is incorrect because client-side encryption is not S3 server-side encryption.
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.
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 company is designing a data protection strategy for its Amazon S3 bucket that stores sensitive customer data. The bucket must be encrypted at rest using a customer managed key (CMK) that is stored in AWS KMS. The company also needs to ensure that only authorized users can decrypt objects. Which TWO actions should the company take?
hard
A.Create a bucket policy that denies s3:GetObject unless the request includes a specific encryption context
✓ B.Modify the KMS key policy to allow only the authorized IAM roles to use the key
✓ C.Attach an IAM policy to the authorized users that grants kms:Decrypt on the CMK
D.Create a VPC endpoint for S3 and use bucket policies to restrict access to the endpoint
E.Use SSE-C with a customer-provided key
Why B: To control decryption access, you need to grant kms:Decrypt permission to authorized users and restrict the key policy accordingly. Option B and D are correct because they control access to the key. Option A is incorrect because a bucket policy alone cannot control decryption; it works with the key policy. Option C is incorrect because SSE-KMS uses KMS keys, not SSE-C. Option E is incorrect because S3 does not support IAM conditions for VPC endpoint on decryption.
Variation 2. A company is storing sensitive data in Amazon S3 buckets. They want to ensure that all uploaded objects are encrypted at rest using server-side encryption with AWS KMS (SSE-KMS). Which bucket policy statement will enforce this?
Why A: Option A is correct because it uses a Deny effect with a StringNotEquals condition on the s3:x-amz-server-side-encryption header set to 'aws:kms'. This ensures that any PutObject request that does not include the header specifying SSE-KMS is denied, effectively enforcing that all uploaded objects must be encrypted with AWS KMS. The Deny effect overrides any Allow, making this policy robust against accidental or malicious uploads without the required encryption.
Variation 3. A company has an Amazon S3 bucket with versioning enabled. They want to ensure that all objects in the bucket are encrypted at rest using server-side encryption with AWS KMS (SSE-KMS). They also want to prevent any future uploads that are not encrypted with SSE-KMS. Which combination of actions should they take?
hard
✓ A.Add a bucket policy that denies s3:PutObject if s3:x-amz-server-side-encryption is not aws:kms. Use S3 Inventory to report encryption status of existing objects.
B.Use AWS Config rule s3-bucket-server-side-encryption-enabled to check compliance.
C.Use S3 Object Lock with governance mode.
D.Enable default encryption with SSE-KMS on the bucket. Use S3 Inventory to report encryption status.
Why A: Option A is correct because a bucket policy denying PutObject without SSE-KMS prevents non-compliant uploads, and S3 Inventory reports encryption status. Option B only checks compliance, does not enforce. Option C does not enforce encryption. Option D does not enforce.
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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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