DEA-C01 Data Security and Governance Practice Question
A team is designing a data lake on S3 and needs to enforce encryption at rest. They want to use server-side encryption with a KMS key that they manage. Which encryption option should they configure on the S3 bucket?
⚠ Common exam trap
It's easy for candidates to confuse SSE-S3 with SSE-KMS, assuming both use customer-managed keys, but SSE-S3 uses AWS-managed keys and does not provide the customer with key management control or audit capabilities.
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
✓
SSE-KMS
SSE-KMS is the correct choice because it provides server-side encryption using a customer-managed KMS key. This allows the team to enforce encryption at rest with their own key, giving them control over key rotation, access policies, and audit trails via AWS CloudTrail, which aligns with the requirement to manage the encryption key themselves.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
SSE-KMS
Why this is correct
SSE-KMS encrypts objects at rest using keys held in AWS KMS, and the customer controls those keys through key policies and grants. This satisfies the requirement for server-side encryption with a customer-managed KMS key on the S3 bucket.
- ✗
Client-side encryption
Why it's wrong here
Client-side encryption encrypts data before upload, so the bucket's server-side configuration never applies and the customer-managed KMS key requirement is unmet. It suits scenarios where the organisation must hold keys entirely outside AWS, such as strict regulatory mandates forbidding provider key custody.
- ✗
SSE-S3
Why it's wrong here
SSE-S3 uses AWS-owned AES-256 keys that the customer cannot manage, view, or audit, so the customer-managed KMS key requirement fails. It suits basic at-rest encryption where key custody, rotation control, and CloudTrail key-usage auditing are not required.
- ✗
SSE-C
Why it's wrong here
SSE-C uses a customer-provided key that Amazon S3 does not store, so key management stays outside AWS KMS entirely. It is tempting because it also delivers server-side encryption at rest. The requirement names a KMS key the team manages, which is SSE-KMS with a customer managed 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 |
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.