MLS-C01 Practice Question: Machine Learning Implementation and Operations
A company uses Amazon SageMaker to train a text classification model. The training data is stored in S3 and contains sensitive personally identifiable information (PII). The company must ensure that the data is encrypted at rest in S3 and that the encryption key is managed by the company's own hardware security module (HSM). Which configuration should be used?
⚠ Common exam trap
Many exam-takers confuse SSE-KMS with customer managed keys as meeting the 'customer-managed' requirement, but the question specifically requires the key to be managed by the company's own HSM, not by AWS KMS, which still stores the key in AWS's infrastructure.
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 server-side encryption with customer-provided keys (SSE-C) and store the keys in the HSM
SSE-C allows you to provide your own encryption key, which can be stored in your own HSM, and Amazon S3 manages the encryption/decryption process using that key. This satisfies the requirement for server-side encryption with a key managed by the company's HSM, ensuring data at rest is encrypted without exposing the key to AWS.
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 server-side encryption with S3-managed keys (SSE-S3)
Why it's wrong here
SSE-S3 uses AWS-managed keys, not customer HSM.
- ✗
Use client-side encryption with the encryption key stored in the HSM
Why it's wrong here
Client-side encryption adds complexity and is not integrated with S3 server-side.
- ✓
Use S3 server-side encryption with customer-provided keys (SSE-C) and store the keys in the HSM
Why this is correct
SSE-C allows customers to provide their own keys, which can be stored in an HSM.
- ✗
Use S3 server-side encryption with AWS KMS managed keys (SSE-KMS) with a customer managed key
Why it's wrong here
KMS is a software key store, not an HSM.
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 MLS-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 MLS-C01 exam.