The answer is to set the default encryption on the S3 bucket to AWS-KMS and specify the customer managed key, while also ensuring the IAM role or user has the kms:Encrypt permission on that key. This is required because SSE-KMS integrates S3 with AWS KMS to encrypt objects at rest using a key you control, and the default encryption setting enforces this policy automatically for every upload, while the kms:Encrypt permission allows the principal to use the key for the encryption operation. On the AWS Certified Data Engineer Associate DEA-C01 exam, this question tests your understanding of the two-part configuration: the bucket-level policy (default encryption) and the IAM-level permissions (KMS actions), with a common trap being that enabling only bucket encryption without granting kms:Encrypt will cause uploads to fail. A helpful memory tip is “Bucket sets the rule, IAM gives the tool”—the bucket enforces the encryption method, but the user or role must have the KMS permission to actually perform the encryption.
DEA-C01 Data Ingestion and Transformation Practice Question
This DEA-C01 practice question tests your understanding of data ingestion and transformation. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. 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 is ingesting large volumes of sensor data into Amazon S3. The data must be encrypted at rest using an AWS KMS customer managed key. Which TWO actions are required to enable server-side encryption with AWS KMS (SSE-KMS) on the S3 bucket?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Set the default encryption on the S3 bucket to AWS-KMS and specify the KMS key
Option B is correct because setting the default encryption on the S3 bucket to AWS-KMS and specifying the KMS key ensures that all objects uploaded to the bucket are automatically encrypted with SSE-KMS using that customer managed key. This is the primary configuration step to enforce server-side encryption at rest with a customer managed key.
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.
✗
Enable S3 Versioning on the bucket
Why it's wrong here
Versioning is not required for SSE-KMS.
✓
Set the default encryption on the S3 bucket to AWS-KMS and specify the KMS key
Why this is correct
This configures SSE-KMS for all objects.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable Amazon CloudWatch Logs for the bucket
Why it's wrong here
Not related to encryption.
✗
Add a bucket policy that denies uploads without encryption
Why it's wrong here
Not required for default encryption.
✓
Ensure the IAM role/user has kms:Encrypt permission on the KMS key
Why this is correct
Without permissions, uploads will fail.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often think a bucket policy denying unencrypted uploads alone is sufficient to enable SSE-KMS, but it only enforces that uploads must include encryption headers—it does not automatically apply encryption, so the default encryption setting is also required.
Detailed technical explanation
How to think about this question
When you set default encryption on an S3 bucket to AWS-KMS, S3 automatically applies SSE-KMS to all new objects using the specified KMS key, even if the upload request does not include encryption headers. The KMS key must be a symmetric customer managed key, and the IAM role/user performing the upload must have the kms:Encrypt permission on that key to allow S3 to call KMS on their behalf. Under the hood, S3 generates a unique data key for each object via KMS GenerateDataKey, encrypts the object with that data key, and stores the encrypted data key alongside the object.
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.
TExam Day Tips
→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 exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Data Ingestion and Transformation — This question tests Data Ingestion and Transformation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Set the default encryption on the S3 bucket to AWS-KMS and specify the KMS key — Option B is correct because setting the default encryption on the S3 bucket to AWS-KMS and specifying the KMS key ensures that all objects uploaded to the bucket are automatically encrypted with SSE-KMS using that customer managed key. This is the primary configuration step to enforce server-side encryption at rest with a customer managed key.
What should I do if I get this DEA-C01 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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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.
Question Discussion
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