DEA-C01 Data Security and Governance Practice Question
A data engineer stores sensitive records in an Amazon S3 bucket. The security team wants to guarantee that every object is encrypted before it is written to disk and that the bucket automatically rejects any unencrypted PUT request, regardless of which IAM principal sends it. Which configuration should the data engineer apply?
⚠ Common exam trap
The trap here is assuming that enabling default bucket encryption prevents unencrypted uploads, when it only supplies encryption for requests that omit the header.
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
✓
Attach a bucket policy that denies s3:PutObject when the request lacks the s3:x-amz-server-side-encryption condition key.
The only mechanism that blocks an unencrypted PUT before the object is stored is a bucket policy using a Deny effect with the s3:x-amz-server-side-encryption condition key. Default encryption and console warnings are passive safeguards that cannot stop an explicit unencrypted request from an SDK or CLI. Block Public Access and lifecycle rules address different concerns entirely.
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 Block Public Access at the account level so that only encrypted objects can be uploaded.
Why it's wrong here
S3 Block Public Access controls public ACLs, public bucket policies, and public access points; it has no relationship to object encryption. Turning it on does not inspect PUT headers or reject unencrypted uploads. An unencrypted object can still be written to a bucket that has all Block Public Access settings enabled, so this does not satisfy the security team's requirement.
- ✗
Enable default bucket encryption with SSE-S3 and rely on the S3 console warning for unencrypted uploads.
Why it's wrong here
Default bucket encryption only applies when a PUT request does not specify an encryption header; a caller can still explicitly send an unencrypted request and S3 will accept it. The console warning is advisory only and does not block API calls from SDKs or third-party tools. This does not meet the requirement to reject every unencrypted PUT request automatically.
- ✗
Configure an S3 Lifecycle rule to transition objects to S3 Glacier Instant Retrieval, which encrypts data at rest.
Why it's wrong here
Lifecycle transitions move objects between storage classes after they are already stored; they do not validate or enforce encryption at write time. S3 Glacier storage classes do encrypt data, but the transition happens asynchronously after the PUT succeeds. An unencrypted object would still be accepted into the bucket first, so this approach cannot prevent the initial unencrypted write.
- ✓
Attach a bucket policy that denies s3:PutObject when the request lacks the s3:x-amz-server-side-encryption condition key.
Why this is correct
A bucket policy with a Deny effect and the s3:x-amz-server-side-encryption condition key rejects any PUT that does not carry a server-side encryption header. This enforces encryption at the bucket level for every principal, including the root account, and works with SSE-S3, SSE-KMS, or DSSE-KMS. It directly satisfies the requirement to block unencrypted writes.
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 |
Go deeper
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
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.