DOP-C02 Security and Compliance Practice Question
A company is using AWS KMS to encrypt data at rest for S3 objects. The security team wants to rotate the KMS key annually. Which action should the team take to implement automatic key rotation?
⚠ Common exam trap
Watch out — candidates often confuse AWS managed keys (which rotate automatically but cannot be configured by the customer) with customer managed keys (which require explicit enabling of automatic rotation), leading them to select Option D incorrectly.
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
✓
Enable automatic key rotation when creating the KMS key
AWS KMS supports automatic annual key rotation for customer managed keys (CMKs) when enabled at creation or via the key's rotation configuration. Once enabled, KMS automatically rotates the key material every 365 days, creating a new backing key while retaining the old one for decryption of previously encrypted data. This satisfies the security team's requirement without manual intervention.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Enable automatic key rotation when creating the KMS key
Why this is correct
Enabling automatic key rotation on a customer-managed KMS key at creation schedules KMS to generate new cryptographic material every 365 days while preserving the same key ID, ARN, and aliases. S3 bucket policies and IAM policies still reference the same key, so no re-encryption of existing objects or policy updates are required. KMS automatically keeps all versions of the backing material available for decryption, so data encrypted before rotation remains decryptable without interruption.
- ✗
Create a new key manually each year and update the S3 bucket policy
Why it's wrong here
Manually creating a new KMS key each year and updating the S3 bucket policy introduces significant operational overhead and risk of misconfiguration. You would have to update every policy that references the old key, manage multiple key versions, and ensure old data remains accessible by keeping the old key enabled. This approach does not provide the seamless transparency of automatic rotation and is prone to human error, potentially causing data access outages if the old key is accidentally disabled or deleted.
- ✗
Use AWS Certificate Manager (ACM) to rotate the KMS key
Why it's wrong here
AWS Certificate Manager (ACM) is specifically designed to issue and manage public SSL/TLS certificates for network traffic encryption, not to manage KMS symmetric keys or their rotation. ACM has no integration with AWS KMS's cryptographic material rotation mechanism, and its lifecycle operations (renewal, distribution) apply only to certificates. Using ACM for rotating a KMS key is conceptually impossible because the services operate at different layers of the encryption stack.
- ✗
Use an AWS managed key, which rotates automatically every year
Why it's wrong here
AWS managed keys such as aws/s3 do rotate automatically every year, but you cannot enable, disable, or schedule that rotation on your own — it is automatically enabled and managed by the respective AWS service. This means you lack the flexibility to control the rotation interval or key policy, which is often required for regulatory compliance or internal security standards. Furthermore, AWS managed keys are shared with other AWS services and do not support customer-managed key policies, so they are not a substitute for a customer-managed key when you need administrative control.
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 |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DOP-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 DOP-C02 exam.