CV0-004 Security Practice Question
A company stores sensitive customer data in an S3 bucket and must encrypt the data at rest using a key managed by the company (not AWS). Which encryption option should the company use?
⚠ Common exam trap
Test-takers frequently confuse SSE-KMS with customer-managed keys: candidates may think 'customer managed key' in KMS means the company manages the key, but the question explicitly says 'not AWS', and SSE-KMS still involves AWS KMS managing the key material, whereas SSE-C requires the customer to provide the key.
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-C
SSE-C (Server-Side Encryption with Customer-Provided Keys) allows the company to provide their own encryption key with each request, and AWS uses that key to encrypt the object at rest but does not store the key. This meets the requirement that the key is managed by the company, not AWS.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Client-side encryption
Why it's wrong here
Client-side encryption requires the company to manage keys and encrypt data before upload, but the question asks for an S3 at-rest encryption option where AWS still performs storage encryption under a company-controlled key. It is tempting because it does give the company full key custody, and it would be correct for data encrypted on-premises before transfer.
- ✓
SSE-C
Why this is correct
SSE-C lets the company supply and retain its own encryption key, which AWS never stores, satisfying the requirement for customer-managed keys. SSE-S3 and SSE-KMS use AWS-managed or AWS-held key material, so neither meets the constraint of company-managed keys.
- ✗
SSE-KMS
Why it's wrong here
SSE-KMS uses AWS KMS customer master keys, so key material and management remain within AWS rather than with the company. It is tempting because customer managed keys in KMS feel company-owned, and SSE-KMS would be correct if the requirement permitted AWS-hosted key management.
- ✗
SSE-S3
Why it's wrong here
SSE-S3 uses AWS-owned and AWS-managed keys, so the company cannot control or rotate them, failing the customer-managed key requirement. It is tempting because it is the default, zero-configuration S3 encryption, and would be the right pick when the organisation has no key-management obligations.
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 CompTIA exam blueprint
This CV0-004 practice question is part of Courseiva's free CompTIA 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 CV0-004 exam.