COF-C03 Data Loading, Unloading, and Connectivity Practice Question
A data engineer needs to unload data from a Snowflake table to an external stage that references an Amazon S3 bucket. The engineer wants to ensure that the unloaded files are encrypted using a customer-managed key in AWS KMS. Which COPY INTO <location> parameter should be used to specify the KMS key?
⚠ Common exam trap
Many candidates confuse S3-managed encryption (AWS_SSE_S3) with customer-managed KMS encryption (AWS_SSE_KMS) and forgetting to include the MASTER_KEY parameter.
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
✓
ENCRYPTION = (TYPE = 'AWS_SSE_KMS' MASTER_KEY = 'arn:aws:kms:...')
To unload data to an external S3 stage with a customer-managed KMS key, the ENCRYPTION parameter must include TYPE = 'AWS_SSE_KMS' and MASTER_KEY set to the KMS key ARN. This ensures server-side encryption with the specified key. Other options either use S3-managed keys, Snowflake-managed encryption, or omit the necessary key parameter, failing to meet the requirement.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
ENCRYPTION = (TYPE = 'SNOWFLAKE_SSE')
Why it's wrong here
SNOWFLAKE_SSE is used for internal stages and applies Snowflake-managed encryption. It is not applicable to external S3 stages and does not support AWS KMS keys. This option is invalid for the scenario because the target is an external S3 stage and the requirement is for a customer-managed KMS key.
- ✗
ENCRYPTION = (TYPE = 'AWS_SSE_KMS')
Why it's wrong here
This option specifies AWS_SSE_KMS but omits the MASTER_KEY parameter. Without the MASTER_KEY, Snowflake cannot specify which KMS key to use, and the unload will fail or use a default key if available. To use a customer-managed key, the MASTER_KEY parameter is required.
- ✓
ENCRYPTION = (TYPE = 'AWS_SSE_KMS' MASTER_KEY = 'arn:aws:kms:...')
Why this is correct
When unloading to an external S3 stage, the ENCRYPTION parameter with TYPE = 'AWS_SSE_KMS' and MASTER_KEY set to the KMS key ARN enables server-side encryption with a customer-managed KMS key. This is the correct syntax to specify the KMS key for the unloaded files, ensuring they are encrypted as required.
- ✗
ENCRYPTION = (TYPE = 'AWS_SSE_S3')
Why it's wrong here
AWS_SSE_S3 uses S3-managed encryption keys, not a customer-managed KMS key. While it provides encryption at rest, it does not allow you to specify a KMS key ARN. This option fails to meet the requirement of using a customer-managed key in AWS KMS.
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 |
About these practice questions
Courseiva writes every COF-C03 question from scratch — 280 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Snowflake exam blueprint
This COF-C03 practice question is part of Courseiva's free Snowflake 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 COF-C03 exam.