DEA-C01 Data Operations and Support Practice Question
A company stores sensitive customer data in an S3 bucket. The data engineer needs to ensure that all data is encrypted at rest. Which S3 feature should be enabled?
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
✓
Default encryption
Default encryption ensures that all new objects written to the bucket are encrypted at rest using SSE-S3, SSE-KMS, or SSE-C. Option A is incorrect because S3 Versioning tracks object versions but does not encrypt data. Option B is incorrect because S3 Block Public Access controls public access, not encryption. Option C is incorrect because the aws:SecureTransport condition enforces encryption in transit, not at rest.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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S3 Versioning
Why it's wrong here
Versioning retains multiple object revisions so overwrites and deletes are recoverable, but it stores each version under the same encryption state as the original. It is tempting because it is a standard S3 data-protection feature, and it would be correct when the requirement is recovering from accidental deletion or overwrite.
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S3 Block Public Access
Why it's wrong here
Block Public Access only overrides ACLs and bucket policies to prevent public exposure; it sets no default encryption and leaves objects stored unencrypted. It is tempting because it is a common S3 hardening setting, and it would be correct when the requirement is stopping accidental public read or write access.
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Bucket policy requiring aws:SecureTransport
Why it's wrong here
This policy condition enforces TLS in transit by rejecting requests where aws:SecureTransport is false; it never applies server-side encryption to stored objects. It is tempting because SecureTransport is a genuine S3 bucket-policy control, but it belongs in scenarios demanding encryption in transit rather than at rest.
- ✓
Default encryption
Why this is correct
Default encryption applies SSE-S3 or SSE-KMS automatically to every object written to the bucket, satisfying the encryption-at-rest requirement without per-request headers. Unlike bucket policies, which only govern access, this setting enforces cryptographic protection at the storage layer itself, covering all uploads including those from unconfigured clients.
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.