DEA-C01 Data Security and Governance Practice Question

A company stores sensitive data in Amazon S3 and requires that all data in transit between on-premises applications and S3 be encrypted. The applications use the AWS SDK to upload and download objects. Which configuration should the data engineer implement to enforce encryption in transit?

⚠ Common exam trap

A common mix-up: candidates confuse encryption at rest (SSE-S3) with encryption in transit, which requires enforcing HTTPS via bucket policies.

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

✓

Configure the S3 bucket policy to deny requests that do not use the aws:SecureTransport condition key.

To enforce encryption in transit for S3, the bucket policy should deny any request that does not use HTTPS, which is indicated by the aws:SecureTransport condition key being false. This ensures that all data transfers between on-premises applications and S3 are encrypted using TLS. Other options address encryption at rest or performance, not in-transit encryption.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

✓
Configure the S3 bucket policy to deny requests that do not use the aws:SecureTransport condition key.
Why this is correct
The aws:SecureTransport condition key checks whether the request was sent over HTTPS. By adding a bucket policy that denies requests where aws:SecureTransport is false, you enforce that all data in transit uses TLS encryption. This is a standard and effective method to enforce encryption in transit for S3.
✗
Enable default encryption on the S3 bucket using SSE-S3.
Why it's wrong here
Default encryption with SSE-S3 encrypts data at rest, not in transit. It does not affect the protocol used for uploading or downloading objects. The requirement is for data in transit, so this option does not address the need for TLS encryption between on-premises applications and S3.
✗
Enable S3 Transfer Acceleration on the bucket to ensure data is encrypted during transfer.
Why it's wrong here
S3 Transfer Acceleration uses AWS edge locations to speed up uploads and downloads, but it does not enforce encryption in transit. It still allows HTTP requests. The feature is for performance, not security, and does not meet the requirement to encrypt data in transit.
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Use AWS Certificate Manager (ACM) to provision a TLS certificate for the S3 bucket.
Why it's wrong here
ACM can provision TLS certificates for use with AWS services like CloudFront or Application Load Balancer, but it cannot be directly attached to an S3 bucket. S3 already supports HTTPS endpoints with Amazon-issued certificates. This option does not enforce encryption in transit and is not a valid configuration for S3.

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

DEA-C01 Data Security and Governance Practice Question

Why each option matters

Option-by-option breakdown

AWS S3 Storage Class Comparison

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