Question 580 of 1,711
DEA-C01 Data Store Management Practice Question
Which TWO options are valid ways to encrypt data at rest in Amazon S3? (Choose two.)
⚠ Common exam trap
Many exam-takers confuse encryption in transit (SSL/TLS) or client-side encryption with data at rest encryption, or mistakenly think IAM policies can encrypt data, when only server-side encryption options (SSE-S3, SSE-KMS, SSE-C) are valid for encrypting data at rest in S3.
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
✓
Server-Side Encryption with S3-Managed Keys (SSE-S3)
Server-Side Encryption with S3-Managed Keys (SSE-S3) is a valid method for encrypting data at rest in Amazon S3 because it uses AES-256 encryption to automatically encrypt objects when they are written to S3 and decrypt them when accessed, with the encryption keys managed entirely by AWS. This option is correct as it directly addresses data at rest encryption within S3, requiring no client-side effort beyond setting the `x-amz-server-side-encryption` header to `AES256`.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Client-Side Encryption
Why it's wrong here
Client-side encryption is performed by the client, not S3.
- ✗
SSL/TLS Encryption
Why it's wrong here
SSL/TLS is for encryption in transit, not at rest.
- ✓
Server-Side Encryption with S3-Managed Keys (SSE-S3)
Why this is correct
SSE-S3 is a server-side encryption option.
- ✗
IAM Policy Encryption
Why it's wrong here
IAM policies control access, not encryption.
- ✓
Server-Side Encryption with AWS KMS-Managed Keys (SSE-KMS)
Why this is correct
SSE-KMS is another server-side encryption option.
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 |
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Last reviewed: Jun 24, 2026
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.
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