Question 212 of 498
VA-003 Explain encryption as a service Practice Question
A data analytics company needs to encrypt streaming data (e.g., clickstream events) before sending to a cloud data lake. Each event is about 1KB. They use Vault Transit to encrypt each event individually. The encryption rate is too slow for the volume (100,000 events/second). The team considers options to improve performance. Which approach is most effective for reducing the number of API calls to Vault while maintaining security?
⚠ Common exam trap
HashiCorp often tests the misconception that Vault's Transit engine can batch multiple data items in a single API call, but Transit only supports single-item encrypt/decrypt operations per request, making envelope encryption the only viable solution for high-throughput streaming data.
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
✓
Generate a local data encryption key (DEK) and encrypt it with Vault's Transit engine (KEK). Encrypt each event locally with the DEK, storing the encrypted DEK alongside the data.
It implements an envelope encryption pattern: a local Data Encryption Key (DEK) encrypts each event locally, avoiding an API call per event, while the DEK itself is encrypted by Vault's Transit engine (Key Encryption Key, KEK). This reduces the number of Vault API calls from 100,000 per second to a single call per DEK rotation, drastically improving throughput without exposing the DEK in plaintext.
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 a different secrets engine like Database or PKI.
Why it's wrong here
Those engines are not designed for bulk encryption of streaming data.
- ✓
Generate a local data encryption key (DEK) and encrypt it with Vault's Transit engine (KEK). Encrypt each event locally with the DEK, storing the encrypted DEK alongside the data.
Why this is correct
Envelope encryption reduces Vault calls to one per DEK rotation, enabling high throughput with minimal API overhead.
- ✗
Increase the number of Vault nodes and load balance requests.
Why it's wrong here
While it improves throughput, it does not reduce the number of API calls per event; each event still requires a call.
- ✗
Use Vault's batch encryption to send multiple events in one request.
Why it's wrong here
Batch encryption can reduce overhead, but the streaming nature makes batching difficult; also, each event still needs to be collected.
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Last reviewed: Jun 30, 2026
This VA-003 practice question is part of Courseiva's free HashiCorp 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 VA-003 exam.
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