The correct answer is to add an S3 bucket policy that denies PutObject if the object is not encrypted using SSE-S3 or SSE-KMS. This works by evaluating the `s3:x-amz-server-side-encryption` condition key at the time of the upload request; if the header is missing or set to a value other than `AES256` or `aws:kms`, the policy explicitly denies the action, blocking the upload entirely. On the AWS Certified Security Specialty SCS-C02 exam, this scenario tests your understanding that default bucket encryption only applies when no encryption header is specified—it does not override a request that explicitly sets encryption to `None`. A common trap is confusing default encryption with a denial policy, or thinking AWS Config can prevent uploads (it can only detect non-compliance). Remember the memory tip: “Default encrypts the lazy, policy denies the defiant”—the bucket policy is the only way to actively reject unencrypted PUT requests.
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 uses Amazon S3 to store sensitive documents. The security team wants to ensure that all objects are encrypted at rest using server-side encryption. Additionally, any attempt to upload an unencrypted object must be denied. What should the security team do?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add an S3 bucket policy that denies PutObject if the object is not encrypted using SSE-S3 or SSE-KMS.
Option D is correct because an S3 bucket policy that denies PutObject if the object is not encrypted ensures that only encrypted objects can be uploaded. Option A is wrong because enabling default encryption does not prevent unencrypted uploads if the request explicitly sets encryption to none. Option B is wrong because AWS Config can detect but not deny the upload. Option C is wrong because S3 does not have an 'encryption required' bucket policy; the correct approach is to deny unencrypted uploads.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Enable default encryption on the S3 bucket using SSE-S3.
Why it's wrong here
Default encryption does not enforce encryption on upload; unencrypted uploads can still occur.
✗
Add an S3 bucket policy that requires encryption using the 's3:x-amz-server-side-encryption' condition key.
Why it's wrong here
The condition key can be used to require encryption, but the correct approach is to deny if encryption is not present.
✓
Add an S3 bucket policy that denies PutObject if the object is not encrypted using SSE-S3 or SSE-KMS.
Why this is correct
Denying unencrypted uploads enforces encryption at upload time.
Related concept
Standard ACLs match source addresses.
✗
Create an AWS Config rule to detect unencrypted objects and trigger a Lambda function to encrypt them.
Why it's wrong here
This is detective, not preventive; does not deny uploads.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SCS-C02 ACL questions on filtering logic and placement.
Data Protection — This question tests Data Protection — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: Add an S3 bucket policy that denies PutObject if the object is not encrypted using SSE-S3 or SSE-KMS. — Option D is correct because an S3 bucket policy that denies PutObject if the object is not encrypted ensures that only encrypted objects can be uploaded. Option A is wrong because enabling default encryption does not prevent unencrypted uploads if the request explicitly sets encryption to none. Option B is wrong because AWS Config can detect but not deny the upload. Option C is wrong because S3 does not have an 'encryption required' bucket policy; the correct approach is to deny unencrypted uploads.
What should I do if I get this SCS-C02 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related SCS-C02 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
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 uses Amazon S3 to store sensitive documents. They must ensure that all objects are encrypted at rest and that any attempt to upload an unencrypted object is denied. Which S3 bucket policy statement achieves this?
hard
A.Deny s3:PutObject unless the request includes x-amz-server-side-encryption: AES256.
B.Deny s3:PutObject for all principals.
✓ C.Deny s3:PutObject unless the request includes x-amz-server-side-encryption: AES256 AND the encryption is SSE-S3.
D.Allow s3:PutObject only when x-amz-server-side-encryption: AES256 is present.
Why C: Option B is correct because it denies PutObject if the request does not include the x-amz-server-side-encryption header with value AES256. Option A is wrong because it only denies if the header is missing, but allows other values. Option C is wrong because it allows only AES256 but does not deny unencrypted. Option D is wrong because it denies all PutObject requests.
Last reviewed: Jun 20, 2026
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.
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
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.