DEA-C01 Data Security and Governance Practice Question
A company stores data in Amazon S3 with server-side encryption using AWS KMS (SSE-KMS). The data engineer needs to give a third-party auditor read-only access to the encrypted objects. The auditor has an AWS account. Which strategy should be used?
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
✓
Update the S3 bucket policy to allow access from the auditor's account and update the KMS key policy to allow the auditor's account to decrypt.
Cross-account access to SSE-KMS encrypted objects requires both an S3 bucket policy allowing the auditor's account and a KMS key policy granting the auditor's account decrypt permissions. Option A is wrong because presigned URLs don't solve the cross-account KMS issue. Option B is wrong because simply granting access to the KMS key is insufficient without S3 permissions. Option C is wrong because copying objects with SSE-S3 changes encryption and may not be allowed.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Generate a presigned URL for each object the auditor needs to access.
Why it's wrong here
Presigned URLs use the creator's credentials but do not work cross-account for KMS.
- ✗
Copy the objects to a new bucket encrypted with SSE-S3 and share that bucket.
Why it's wrong here
Copying might not be feasible and SSE-S3 is not KMS.
- ✗
Grant the auditor's IAM role permission to use the KMS key.
Why it's wrong here
They also need S3 permissions to read the objects.
- ✓
Update the S3 bucket policy to allow access from the auditor's account and update the KMS key policy to allow the auditor's account to decrypt.
Why this is correct
Both policies are required for cross-account access with SSE-KMS.
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.