- A
The key material was imported incorrectly. Delete the key ring and recreate it using an external HSM.
Why wrong: There is no indication of import issues.
- B
The automatic backups in Cloud SQL are encrypted with the primary key version at backup time, but the backup restore functionality does not automatically use the latest key version. Update the backup configuration to use the current primary key version for decryption.
Cloud SQL restore requires referencing the correct key version; re-associating the backup with the latest key version allows decryption.
- C
The rotation period of 30 days is too short for key retention. Disable automatic rotation and use manual key rotation every 30 days while retaining all versions.
Why wrong: Manual rotation is not required and does not solve the decryption issue.
- D
Cloud Storage does not support Cloud HSM keys for object encryption. Switch to customer-supplied encryption keys (CSEK).
Why wrong: Cloud Storage supports Cloud HSM keys.
Quick Answer
The answer is that the backup restore fails because Cloud SQL encrypts each backup with the primary Cloud HSM key version at the time of creation, and the restore process does not automatically reference the correct historical key version after rotation. Even though all key versions remain available in Cloud HSM, the restore operation cannot locate the specific version used to encrypt the older backup unless the backup configuration is explicitly updated to point to the current primary key version. This scenario tests your understanding of how Cloud HSM key versioning interacts with Cloud SQL backup lifecycle management—a common exam trap is assuming that simply retaining key versions guarantees decryption, when in fact the restore operation requires an explicit reference to the appropriate version. On the Google Professional Cloud Security Engineer exam, remember that key rotation breaks the implicit link between backups and their encryption keys; you must update the backup configuration to re-establish that link. Memory tip: “Backups lock in the key version at birth; restore needs a map to find it.”
PCSE Ensuring data protection Practice Question
This PCSE practice question tests your understanding of ensuring data protection. 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 global e-commerce company uses Google Cloud to host its platform. They store customer payment data in Cloud SQL and use Cloud Storage for backups. Currently, they rely on Google-managed encryption keys. A new compliance requirement mandates that all encryption keys must be stored in a hardware security module (HSM) and rotated every 30 days. Additionally, they need to retain backup data for 7 years, during which the keys used to encrypt the backups must be available for decryption. They have created a Cloud HSM key ring and a key with a rotation period of 2592000 seconds (30 days). After configuring Cloud SQL and Cloud Storage to use the Cloud HSM key, they notice that backups older than 30 days cannot be decrypted. The company's security engineer verified that the key versions are still present. What is the most likely cause and how should it be resolved?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
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.
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 automatic backups in Cloud SQL are encrypted with the primary key version at backup time, but the backup restore functionality does not automatically use the latest key version. Update the backup configuration to use the current primary key version for decryption.
Option B is correct because Cloud SQL backups are encrypted with the primary key version at the time of backup creation. When restoring a backup, Cloud SQL does not automatically use the latest key version; it attempts to decrypt using the key version that was primary at backup time. Since the key is rotated every 30 days, backups older than 30 days were encrypted with a previous primary key version. Even though the key versions are still present in Cloud HSM, the backup restore operation fails because it does not automatically reference the correct historical key version. The fix is to explicitly update the backup configuration to point to the current primary key version, which allows Cloud SQL to locate and use the appropriate 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 material was imported incorrectly. Delete the key ring and recreate it using an external HSM.
Why it's wrong here
There is no indication of import issues.
- ✓
The automatic backups in Cloud SQL are encrypted with the primary key version at backup time, but the backup restore functionality does not automatically use the latest key version. Update the backup configuration to use the current primary key version for decryption.
Why this is correct
Cloud SQL restore requires referencing the correct key version; re-associating the backup with the latest key version allows decryption.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The rotation period of 30 days is too short for key retention. Disable automatic rotation and use manual key rotation every 30 days while retaining all versions.
Why it's wrong here
Manual rotation is not required and does not solve the decryption issue.
- ✗
Cloud Storage does not support Cloud HSM keys for object encryption. Switch to customer-supplied encryption keys (CSEK).
Why it's wrong here
Cloud Storage supports Cloud HSM keys.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that key rotation automatically updates all existing encrypted data, when in reality each encryption operation uses the key version that was primary at that time, and decryption requires explicit reference to the correct historical version.
Detailed technical explanation
How to think about this question
Under the hood, Cloud SQL uses Cloud KMS to encrypt backups, and each backup is associated with the primary key version at the time of encryption. When a restore is initiated, Cloud SQL looks up the key version ID stored in the backup metadata. If the key has been rotated, the primary key version changes, and the backup metadata still references the old version. The restore fails unless the old key version is explicitly enabled and accessible. In practice, you must ensure that all historical key versions remain enabled and that the backup configuration is updated to point to the correct key version, or use a key with a longer rotation period combined with version retention to avoid this issue.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
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.
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Ensuring data protection — study guide chapter
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FAQ
Questions learners often ask
What does this PCSE question test?
Ensuring data protection — This question tests Ensuring data protection — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The automatic backups in Cloud SQL are encrypted with the primary key version at backup time, but the backup restore functionality does not automatically use the latest key version. Update the backup configuration to use the current primary key version for decryption. — Option B is correct because Cloud SQL backups are encrypted with the primary key version at the time of backup creation. When restoring a backup, Cloud SQL does not automatically use the latest key version; it attempts to decrypt using the key version that was primary at backup time. Since the key is rotated every 30 days, backups older than 30 days were encrypted with a previous primary key version. Even though the key versions are still present in Cloud HSM, the backup restore operation fails because it does not automatically reference the correct historical key version. The fix is to explicitly update the backup configuration to point to the current primary key version, which allows Cloud SQL to locate and use the appropriate key version for decryption.
What should I do if I get this PCSE 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: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 30, 2026
This PCSE practice question is part of Courseiva's free Google Cloud 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 PCSE exam.
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