DEA-C01 Data Security and Governance Practice Question
A company has a data lake in Amazon S3 with millions of objects. The security team wants to enforce that all objects are encrypted with a specific customer-managed KMS key. The data engineer configures an S3 bucket policy to deny PutObject if the encryption is not set to that key. However, some existing objects are not encrypted with that key. What is the most efficient way to remediate the existing objects?
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
✓
Use S3 Batch Operations to copy objects in the same bucket with the new encryption settings.
S3 Batch Operations can copy objects within the same bucket with new encryption settings, efficiently updating millions of objects in place. Option A is incorrect because S3 Cross-Region Replication replicates objects to a different bucket or region, not to the same bucket with changed encryption. Option B is inefficient compared to Batch Operations for large-scale remediation. Option D is incorrect because S3 Object Lambda transforms data on read, not at rest, so it does not change the stored encryption of existing objects.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use S3 Cross-Region Replication to replicate objects to a new bucket with the correct encryption.
Why it's wrong here
Replication does not change encryption of existing objects in the same bucket.
- ✗
Write a script using the AWS SDK to iterate over all objects and re-upload them with the correct encryption.
Why it's wrong here
Inefficient and time-consuming for millions of objects.
- ✓
Use S3 Batch Operations to copy objects in the same bucket with the new encryption settings.
Why this is correct
Batch Operations can efficiently update encryption for large numbers of objects.
- ✗
Use S3 Object Lambda to dynamically encrypt objects on read.
Why it's wrong here
Object Lambda does not modify objects at rest.
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.