MLS-C01 Data Engineering Practice Question
A company is designing a data pipeline to ingest data from multiple sources into an Amazon S3 data lake. The data must be encrypted at rest and in transit. Which TWO actions should be taken to meet these requirements?
⚠ Common exam trap
Watch out — candidates often confuse S3 Transfer Acceleration or VPC Endpoints with encryption features, or mistakenly think client-side encryption is required alongside server-side encryption, when the simplest AWS-native pair is SSE + HTTPS enforcement.
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
✓
Enable Server-Side Encryption on the S3 bucket
Enabling Server-Side Encryption (SSE-S3 or SSE-KMS) on the S3 bucket automatically encrypts data at rest when written to disk, using AES-256 encryption. This meets the requirement for encryption at rest without any client-side changes.
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 Server-Side Encryption on the S3 bucket
Why this is correct
Encrypts objects at rest.
- ✗
Enable S3 Transfer Acceleration
Why it's wrong here
Acceleration improves speed, not encryption.
- ✓
Enforce HTTPS for all S3 API requests using bucket policy
Why this is correct
Ensures data is encrypted in transit.
- ✗
Use client-side encryption before uploading
Why it's wrong here
Not required; server-side encryption is sufficient.
- ✗
Use S3 VPC Endpoint
Why it's wrong here
VPC endpoints provide private connectivity but do not encrypt.
Quick reference
Symmetric Encryption Algorithm Comparison
| Algorithm | Key Size | Block Size | Status | Notes |
|---|---|---|---|---|
| AES-128 | 128-bit | 128-bit | Current standard | NIST approved; WPA3, TLS |
| AES-256 | 256-bit | 128-bit | Current standard | Preferred for sensitive / govt data |
| 3DES | 112-bit effective | 64-bit | Deprecated (2023) | Replaced by AES |
| DES | 56-bit | 64-bit | Broken | Cracked in < 24 h; never deploy |
| ChaCha20 | 256-bit | Stream cipher | Current | TLS 1.3, WireGuard |
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.