DEA-C01 Data Security and Governance Practice Question
A data engineer needs to encrypt data at rest in Amazon S3 using server-side encryption with a customer-managed KMS key. Which TWO steps are required to ensure that the KMS key can be used for S3 object encryption?
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
✓
Add a statement in the KMS key policy that allows the S3 service to use the key.
Options C and D are correct. For SSE-KMS with a customer-managed key, the KMS key policy must include a statement that allows the S3 service to use the key (e.g., kms:GenerateDataKey and kms:Decrypt). Additionally, the IAM role writing objects must have kms:GenerateDataKey and kms:Decrypt permissions. Option A is not required because a VPC endpoint for KMS is not mandatory for S3 to access the key. Option B is not required because enforcing SSE-KMS via bucket policy is a separate configuration, not a prerequisite for using the key. Option E is not required because S3 does not use a service-linked role for KMS access.
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 a VPC endpoint for KMS to allow S3 to access the key.
Why it's wrong here
Not required for SSE-KMS.
- ✗
Set the S3 bucket policy to require SSE-KMS for all PutObject requests.
Why it's wrong here
This enforces encryption but does not grant KMS permissions.
- ✓
Add a statement in the KMS key policy that allows the S3 service to use the key.
Why this is correct
The key policy must allow S3 to call GenerateDataKey and Decrypt.
- ✓
Grant the IAM role that writes objects the kms:GenerateDataKey and kms:Decrypt permissions.
Why this is correct
The IAM role must have permissions to use the KMS key.
- ✗
Create a service-linked role for S3 to access KMS.
Why it's wrong here
S3 does not use a service-linked role for SSE-KMS.
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 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.