DEA-C01 Data Security and Governance Practice Question
A data engineer needs to ensure that all data stored in an Amazon S3 bucket is encrypted at rest using a customer managed key in AWS KMS. The engineer also needs to enforce that any attempt to upload an object without specifying the correct KMS key is denied. Which combination of actions should the engineer take?
⚠ Common exam trap
The trap here is assuming that enabling default encryption alone enforces the use of a specific KMS key, when in fact uploads can override the default with a different encryption method unless a bucket policy explicitly denies it.
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
✓
Enable default encryption on the bucket with SSE-KMS using the customer managed key, and add a bucket policy that denies s3:PutObject requests that do not include the correct x-amz-server-side-encryption header.
To enforce encryption with a specific customer managed KMS key, enable default SSE-KMS encryption on the bucket and add a bucket policy that denies PutObject requests unless they include the correct x-amz-server-side-encryption header. This ensures all objects are encrypted with the designated key and prevents uploads with other encryption methods.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Configure the bucket to use SSE-KMS with the customer managed key and attach an IAM policy to all users that allows only s3:PutObject with the correct encryption header.
Why it's wrong here
IAM policies can be used, but they are not as centralized or enforceable as a bucket policy. A bucket policy applies to all principals accessing the bucket, ensuring consistent enforcement. Relying on IAM policies alone may leave gaps if new users are added without the policy.
- ✗
Enable default encryption with SSE-S3 and use AWS KMS grants to restrict access to the customer managed key.
Why it's wrong here
SSE-S3 uses S3-managed keys, not customer managed KMS keys. The requirement specifies a customer managed key in AWS KMS. KMS grants control access to the key but do not enforce encryption type on uploads. This approach fails to meet the encryption requirement.
- ✗
Use an S3 Object Lambda access point to encrypt objects on upload with the customer managed key.
Why it's wrong here
S3 Object Lambda is used to transform data on retrieval, not on upload. It cannot enforce encryption at rest. The requirement is to enforce encryption on upload, which is better handled by bucket policies and default encryption.
- ✓
Enable default encryption on the bucket with SSE-KMS using the customer managed key, and add a bucket policy that denies s3:PutObject requests that do not include the correct x-amz-server-side-encryption header.
Why this is correct
Default encryption ensures all objects are encrypted with the specified KMS key, but it does not prevent uploads with a different encryption method. A bucket policy that denies PutObject requests lacking the correct encryption header enforces the use of the specific KMS key. Together, they meet the requirement.
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
Related to this question
About these practice questions
This DEA-C01 question is part of Courseiva's 1,321-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
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.