The correct answer is to modify the bucket policy to deny PutObject and GetObject unless the request includes the specific KMS key ID in the 'x-amz-server-side-encryption-aws-kms-key-id' header. This works because the bucket policy uses the `s3:x-amz-server-side-encryption-aws-kms-key-id` condition key to enforce SSE-KMS encryption at the object level, ensuring only objects encrypted with the security team’s specific KMS key are accessible. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding of how to enforce S3 encryption using bucket policy as a preventive control, often appearing as a trap where candidates confuse default encryption (SSE-S3) with key-level enforcement. A common mistake is choosing SSE-C or SSE-S3, but remember: SSE-S3 lacks key control, and SSE-C cannot be audited via bucket policies. Memory tip: “Deny without the key ID” — if the request lacks your specific KMS key, the bucket policy blocks both uploads and downloads.
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 stores sensitive data in an S3 bucket with default encryption (SSE-S3) enabled. A security audit reveals that objects are being accessed by users from unexpected IP addresses. The company wants to enforce that only objects encrypted with a specific KMS key (managed by the security team) can be accessed. Which combination of actions should be taken?
Use SSE-C and distribute the customer key to authorized users only.
Why wrong: SSE-C does not provide centralized key management and audit.
B
Modify the bucket policy to deny PutObject and GetObject unless the request includes the specific KMS key ID in the 'x-amz-server-side-encryption-aws-kms-key-id' header.
This enforces use of the specific KMS key for all operations.
C
Enable S3 Block Public Access and use AWS WAF to filter IP addresses.
Why wrong: Block Public Access and WAF do not enforce encryption key usage.
D
Apply an S3 Lifecycle policy to transition objects to Glacier after 30 days.
Why wrong: Lifecycle policy does not control access based on encryption.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Modify the bucket policy to deny PutObject and GetObject unless the request includes the specific KMS key ID in the 'x-amz-server-side-encryption-aws-kms-key-id' header.
Option C is correct because using a bucket policy to deny access unless the request includes the specific KMS key via the 's3:x-amz-server-side-encryption-aws-kms-key-id' condition key enforces the requirement. Option A is wrong because SSE-S3 does not allow key-level control. Option B is wrong because SSE-C is not auditable in the same way. Option D is wrong because it does not restrict access based on encryption key.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Use SSE-C and distribute the customer key to authorized users only.
Why it's wrong here
SSE-C does not provide centralized key management and audit.
✓
Modify the bucket policy to deny PutObject and GetObject unless the request includes the specific KMS key ID in the 'x-amz-server-side-encryption-aws-kms-key-id' header.
Why this is correct
This enforces use of the specific KMS key for all operations.
Related concept
Static NAT maps one inside address to one outside address.
✗
Enable S3 Block Public Access and use AWS WAF to filter IP addresses.
Why it's wrong here
Block Public Access and WAF do not enforce encryption key usage.
✗
Apply an S3 Lifecycle policy to transition objects to Glacier after 30 days.
Why it's wrong here
Lifecycle policy does not control access based on encryption.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SCS-C02 NAT questions on configuration and troubleshooting.
Data Protection — This question tests Data Protection — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Modify the bucket policy to deny PutObject and GetObject unless the request includes the specific KMS key ID in the 'x-amz-server-side-encryption-aws-kms-key-id' header. — Option C is correct because using a bucket policy to deny access unless the request includes the specific KMS key via the 's3:x-amz-server-side-encryption-aws-kms-key-id' condition key enforces the requirement. Option A is wrong because SSE-S3 does not allow key-level control. Option B is wrong because SSE-C is not auditable in the same way. Option D is wrong because it does not restrict access based on encryption key.
What should I do if I get this SCS-C02 question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related SCS-C02 NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
About these practice questions
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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 stores sensitive customer data in an S3 bucket. The security team requires that all data be encrypted at rest using a customer-managed KMS key. What should the team configure to enforce this requirement?
easy
✓ A.Add a bucket policy that denies s3:PutObject unless the request includes the x-amz-server-side-encryption-aws:kms header.
B.Enable S3 Block Public Access.
C.Configure S3 Object Lock to require encryption.
D.Enable default encryption on the S3 bucket with AES-256.
Why A: Option D is correct because using a bucket policy that denies PutObject if the request does not include the correct encryption header (aws:kms) ensures that any upload without KMS encryption is denied. Option A is wrong because enabling default encryption does not prevent unencrypted uploads; it applies encryption server-side but still allows uploads without explicit encryption headers. Option B is wrong because S3 Object Lock is for write-once-read-many protection, not encryption enforcement. Option C is wrong because enabling S3 Block Public Access does not enforce encryption.
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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