CV0-004 Security Practice Question
A financial services company stores regulated data in Amazon S3 buckets. A security architect must ensure that objects are encrypted at rest using keys that the company controls, can be rotated on a schedule, and can be audited independently of AWS-managed keys. The keys must not leave AWS hardware security modules in plaintext. Which encryption option should the architect choose?
⚠ Common exam trap
Many candidates confuse customer-controlled keys with customer-provided keys, assuming SSE-C provides the same audit and rotation benefits as a KMS customer managed 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-KMS with a customer managed key in AWS KMS
SSE-KMS with a customer managed key gives the company ownership of the key policy, scheduled rotation, and an audit trail via CloudTrail and KMS logs, while the key material remains protected inside AWS KMS HSMs. This matches the control, rotation, and auditability requirements.
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 with a customer managed key in AWS KMS
Why this is correct
SSE-KMS with a customer managed key lets the company define key policies, enable automatic rotation, and audit every use through CloudTrail and KMS key usage logs. The key material is protected by AWS KMS HSMs and never leaves them in plaintext. This satisfies control, scheduled rotation, and independent auditability for the regulated data.
- ✗
SSE-S3 with bucket default encryption
Why it's wrong here
SSE-S3 uses AWS-managed keys that the customer cannot view, rotate on their own schedule, or audit through a separate key policy. While it encrypts objects at rest, it does not provide the customer-controlled key lifecycle or independent audit trail the architect requires. It is the simplest option but fails the control and auditability criteria.
- ✗
SSE-C with customer-provided keys
Why it's wrong here
SSE-C requires the customer to supply the encryption key with every request, and AWS does not store it. This means rotation and auditability are entirely the customer's responsibility, and there is no KMS key policy or CloudTrail key-use trail. It also complicates lifecycle and replication. It does not meet the requirement for scheduled rotation and independent audit of key usage.
- ✗
Client-side encryption before uploading to S3
Why it's wrong here
Client-side encryption puts key management fully in the customer's environment, which can meet control goals but pushes rotation, HSM protection, and audit entirely outside AWS. The requirement states keys must not leave AWS HSMs in plaintext, which points to KMS-backed encryption. Client-side also breaks some S3 features such as range GETs and certain analytics.
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.