DVA-C02 Security Practice Question
A company requires that all data in an S3 bucket be encrypted at rest. The security team wants to enforce that only objects encrypted with AWS KMS are allowed. Which S3 bucket policy condition key should be used to deny PutObject requests if the object is not encrypted with KMS?
⚠ Common exam trap
A common mix-up: candidates confuse the valid condition key `s3:x-amz-server-side-encryption-aws-kms-key-id` with similar-sounding but invalid keys like `s3:x-amz-server-side-encryption-kms-key-id` (missing 'aws') or `s3:x-amz-server-side-encryption-key-id` (which does not exist), leading them to choose an option that AWS S3 will not evaluate.
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
✓
s3:x-amz-server-side-encryption-aws-kms-key-id
The `s3:x-amz-server-side-encryption-aws-kms-key-id` condition key specifically checks for the AWS KMS key ID (or alias) used for server-side encryption with AWS KMS (SSE-KMS). By using this key in a bucket policy with a `Deny` effect, you can enforce that only objects encrypted with a specific KMS key are allowed, rejecting any `PutObject` request that does not include the required `x-amz-server-side-encryption-aws-kms-key-id` header.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
s3:x-amz-server-side-encryption-key-id
Why it's wrong here
This is not a valid condition key in S3 bucket policies.
- ✗
s3:x-amz-server-side-encryption
Why it's wrong here
This condition key only checks if encryption is enabled, not the specific KMS key.
- ✗
s3:x-amz-server-side-encryption-kms-key-id
Why it's wrong here
This is not a valid condition key in S3 bucket policies.
- ✓
s3:x-amz-server-side-encryption-aws-kms-key-id
Why this is correct
This condition key allows you to require a specific KMS key ID.
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 DVA-C02 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 DVA-C02 exam.