DEA-C01 Data Operations and Support Practice Question
A company uses Amazon S3 as a data lake. A data engineer needs to ensure that all objects uploaded to the 'incoming' prefix are automatically encrypted at rest using AWS KMS with a specific customer managed key. What is the simplest way to enforce this?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use a bucket policy that denies PutObject requests without the required encryption header.
A bucket policy with a condition that denies PutObject requests unless the request includes the required encryption headers (x-amz-server-side-encryption: aws:kms and x-amz-server-side-encryption-aws-kms-key-id with the specific customer managed key ARN) enforces encryption at rest using that key. Option A (S3 Transfer Acceleration) only optimizes transfer speed, not encryption at rest. Option C (S3 Inventory) reports on encryption status but does not enforce it. Option D (default encryption with SSE-S3) uses S3-managed keys, not a customer managed KMS key, so it does not meet the requirement.
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 S3 Transfer Acceleration to force encryption in transit.
Why it's wrong here
Transfer Acceleration only improves speed, not encryption at rest.
- ✓
Use a bucket policy that denies PutObject requests without the required encryption header.
Why this is correct
A bucket policy with a condition for s3:x-amz-server-side-encryption-aws-kms-key-id enforces the specific key.
- ✗
Configure S3 Inventory to report on encryption status and alert on non-compliance.
Why it's wrong here
Inventory reports, but does not prevent unencrypted uploads.
- ✗
Enable default encryption on the bucket with SSE-S3.
Why it's wrong here
Default encryption uses SSE-S3 by default, not customer managed KMS key.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 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 DEA-C01 exam.