The correct answer is a KMS key policy that grants the kms:Decrypt permission to the specific IAM role. This works because AWS KMS uses key policies as the primary access control mechanism for customer master keys (CMKs); by explicitly allowing only the designated IAM role to perform decryption, you effectively restrict all other principals—including the root user and other roles—from decrypting the S3 backup files. On the AWS Certified Database Specialty DBS-C01 exam, this scenario tests your understanding of how to combine SSE-KMS with IAM-based access control, often appearing as a distractor where candidates mistakenly choose an S3 bucket policy or an IAM role trust policy. A common trap is assuming that an S3 bucket policy can override KMS permissions, but KMS key policies are the authoritative gate for decrypt operations. Memory tip: think of the KMS key policy as the bouncer at the door—only the role with the kms:Decrypt stamp on its ID gets in.
DBS-C01 Database Security Practice Question
This DBS-C01 practice question tests your understanding of database security. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company has an Amazon S3 bucket that stores database backup files. The backups are encrypted using server-side encryption with AWS KMS (SSE-KMS). The security team wants to ensure that only a specific IAM role can decrypt the backups when restoring the database. Which policy should be attached to the KMS key to achieve this?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
A KMS key policy that grants kms:Decrypt to the IAM role.
Option D is correct because a KMS key policy can grant the kms:Decrypt permission to a specific IAM role. Option A does not restrict decryption. Option B is for S3 bucket policy, not KMS. Option C is for S3, not KMS.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
An S3 bucket policy that grants kms:Decrypt to the IAM role.
Why it's wrong here
S3 bucket policies cannot grant KMS permissions.
✗
An S3 bucket policy that grants s3:GetObject to the IAM role.
Why it's wrong here
The S3 bucket policy controls access to the object, not decryption of the key.
✗
An IAM policy attached to the role that grants kms:Decrypt.
Why it's wrong here
The KMS key policy must also allow the role; otherwise, the IAM policy alone is insufficient if the key policy denies.
✓
A KMS key policy that grants kms:Decrypt to the IAM role.
Why this is correct
The KMS key policy controls who can use the key for decryption.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
Got this wrong? Here's your next step.
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Database Security — This question tests Database Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: A KMS key policy that grants kms:Decrypt to the IAM role. — Option D is correct because a KMS key policy can grant the kms:Decrypt permission to a specific IAM role. Option A does not restrict decryption. Option B is for S3 bucket policy, not KMS. Option C is for S3, not KMS.
What should I do if I get this DBS-C01 question wrong?
Identify which DBS-C01 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This DBS-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 DBS-C01 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.