Question 273 of 514
Explain encryption as a serviceeasyMultiple ChoiceObjective-mapped

Quick Answer

The answer is that the application is not specifying the key version in the decryption request, so Vault defaults to the latest key version, which cannot decrypt data encrypted with the old version. This happens because when a transit key is rotated, Vault creates a new key version while preserving the old one for legacy decryption, but decryption requests without a version parameter always target the newest version. On the HashiCorp Vault Associate VA-003 exam, this scenario tests your understanding of the transit secrets engine’s key versioning behavior and the critical role of the `?version=` parameter in decryption operations. A common trap is assuming Vault automatically selects the correct version based on the ciphertext, but it does not—you must explicitly specify the version or use the `rewrap` endpoint to re-encrypt data under the new key. Remember: after transit decryption fails after key rotation version parameter omission, always check that your application is targeting the correct key version. Memory tip: “No version? No decryption—Vault picks the newest, not the one that brewed it.”

VA-003 Explain encryption as a service Practice Question

This VA-003 practice question tests your understanding of explain encryption as a service. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.

A financial technology company uses Vault Enterprise to manage encryption keys for its payment processing system. The system uses the transit secrets engine to encrypt credit card numbers before storing them in a legacy database. The security team mandates that all encryption keys must be automatically rotated every 30 days. The operations team configures the key 'payment-cards' with 'auto_rotate_period' set to 30 days. After the first rotation, the payment processing application starts failing with 'permission denied' errors when trying to decrypt previously encrypted data. The application uses a token with a policy that grants 'create' and 'update' capabilities on 'transit/decrypt/payment-cards'. The application does not use the 'rewrap' endpoint. The Vault audit logs show that the decryption requests are being made to the correct path. What is the most likely cause of the failure?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "first"

    Why it matters: Order matters here. You are being tested on which action comes before the others — not which action is generally useful.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Question 1easymultiple choice
Read the full NAT/PAT explanation →

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 application is not specifying the key version in the decryption request, and Vault defaults to the latest key version which cannot decrypt data encrypted with the old version.

Option D is correct because when Vault rotates a key in the transit secrets engine, it creates a new key version but retains the old version for decryption of existing ciphertexts. By default, decryption requests that do not specify a key version use the latest version, which cannot decrypt data encrypted with an older version. The application must explicitly include the `?version=` parameter or use the ciphertext's embedded version information to target the correct key version for decryption.

Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

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 key rotation changed the encryption algorithm, making old ciphertexts incompatible with the new key.

    Why it's wrong here

    Key rotation does not change the algorithm; it only creates a new key version.

  • The application's token has expired after the key rotation, requiring a new token with updated policies.

    Why it's wrong here

    Token expiration is unrelated to key rotation; the token should still be valid unless its TTL has passed.

  • The application must use the 'rewrap' endpoint to re-encrypt all ciphertexts with the new key version before decryption.

    Why it's wrong here

    Rewrapping is optional; the application can still decrypt using the old key version if it specifies the correct ciphertext context.

  • The application is not specifying the key version in the decryption request, and Vault defaults to the latest key version which cannot decrypt data encrypted with the old version.

    Why this is correct

    By default, Vault uses the latest key version for decryption. To decrypt with an older version, the ciphertext must include a version reference, or the application must use the 'rewrap' endpoint.

    Clue confirmation

    The clue words "first", "most likely" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

Common exam traps

Common exam trap: answer the scenario, not the keyword

The trap here is that candidates assume key rotation automatically makes old ciphertexts decryptable with the new key, when in fact Vault requires explicit version targeting or use of the ciphertext's embedded version metadata to decrypt with the correct key version.

Detailed technical explanation

How to think about this question

Under the hood, Vault's transit secrets engine uses key versioning where each rotation increments the version number. The ciphertext output by the `encrypt` endpoint includes a version prefix (e.g., `vault:v1:...`), but if the application strips or ignores this prefix, the decryption request defaults to the latest key version. In real-world scenarios, applications must either pass the ciphertext as-is (which includes version metadata) or explicitly set the `key_version` parameter in the decryption API call to match the version used during encryption.

KKey Concepts to Remember

  • Read the scenario before looking for a memorised answer.
  • Find the constraint that changes the correct option.
  • Eliminate answers that are true in general but not in this case.

TExam Day Tips

  • Watch for words such as best, first, most likely and least administrative effort.
  • Review why wrong options are wrong, not only why the correct option is correct.

Key takeaway

Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.

Real-world example

How this comes up in practice

A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.

What to study next

Got this wrong? Here's your next step.

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Related practice questions

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FAQ

Questions learners often ask

What does this VA-003 question test?

Explain encryption as a service — This question tests Explain encryption as a service — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The application is not specifying the key version in the decryption request, and Vault defaults to the latest key version which cannot decrypt data encrypted with the old version. — Option D is correct because when Vault rotates a key in the transit secrets engine, it creates a new key version but retains the old version for decryption of existing ciphertexts. By default, decryption requests that do not specify a key version use the latest version, which cannot decrypt data encrypted with an older version. The application must explicitly include the `?version=` parameter or use the ciphertext's embedded version information to target the correct key version for decryption.

What should I do if I get this VA-003 question wrong?

Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.

Are there clue words in this question I should notice?

Yes — watch for: "first", "most likely". Order matters here. You are being tested on which action comes before the others — not which action is generally useful.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 11, 2026

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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.