VA-003 Explain encryption as a service Practice Question
Exhibit
Error making API request. URL: POST http://vault.example.com/v1/transit/decrypt/mykey Code: 400. Errors: * invalid ciphertext: invalid base64 string
Refer to the exhibit. A developer receives this error when attempting to decrypt data. What is the most likely cause?
⚠ Common exam trap
HashiCorp often tests the distinction between encoding errors (base64) and cryptographic errors (key mismatch, permissions) to see if candidates understand that Vault validates input format before attempting decryption.
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
✓
The ciphertext provided is not valid base64
The error indicates that the ciphertext provided is not valid base64. Vault's transit engine expects ciphertext to be base64-encoded; if the input is malformed or not properly encoded, the decryption operation fails with this specific error. This is the most direct cause given the error message.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The ciphertext is encrypted with a different key
Why it's wrong here
Would result in a different error, likely 'invalid ciphertext' but not base64 related.
- ✗
The Vault server is not configured with the transit engine
Why it's wrong here
Would return a 404 for the path.
- ✗
The key mykey does not exist
Why it's wrong here
Would result in a 404 error, not 400 with this message.
- ✓
The ciphertext provided is not valid base64
Why this is correct
Directly matches the error message.
- ✗
The token used does not have permission to decrypt
Why it's wrong here
Would return a 403 error.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.