Google PCA Design for security and compliance Practice Question
A company is migrating its on-premises workloads to Google Cloud. They have strict compliance requirements that all data at rest must be encrypted with customer-managed encryption keys (CMEK). Which Google Cloud service should they use to manage the lifecycle of these keys?
⚠ Common exam trap
Many candidates confuse Cloud HSM as a key management service, but Cloud HSM is a key storage backend for Cloud KMS, not a replacement for lifecycle management; you must use Cloud KMS to control key creation, rotation, and destruction even when using HSM-backed keys.
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
✓
Cloud Key Management Service (Cloud KMS)
Cloud KMS is the correct service because it provides centralized management of customer-managed encryption keys (CMEK) for Google Cloud services. It allows you to create, rotate, destroy, and set permissions on symmetric and asymmetric keys, and integrates directly with services like Cloud Storage, BigQuery, and Compute Engine to enforce encryption at rest with keys you control.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Secret Manager
Why it's wrong here
Secret Manager stores and versions secrets such as API keys and passwords; it does not generate or manage the encryption keys that protect data at rest. It is tempting because it handles credential lifecycle, which is the correct choice when the requirement is rotating application secrets rather than CMEK.
- ✗
Cloud External Key Manager (Cloud EKM)
Why it's wrong here
Cloud EKM keeps key material outside Google Cloud in an external manager, so the keys are externally managed rather than customer-managed within Cloud KMS. It is tempting because it satisfies sovereignty requirements demanding keys never reside in Google infrastructure, which is a different compliance goal.
- ✓
Cloud Key Management Service (Cloud KMS)
Why this is correct
Cloud KMS creates, stores, rotates and controls customer-managed encryption keys, and integrates with Google Cloud services so data at rest is encrypted under CMEK. It directly satisfies the compliance requirement for managing key lifecycle rather than relying on Google-managed keys.
- ✗
Cloud Hardware Security Module (Cloud HSM)
Why it's wrong here
Cloud HSM provides hardware-backed key storage within Cloud KMS but is a protection level, not the lifecycle management service itself; keys are still created and rotated in Cloud KMS. It is tempting because it meets FIPS 140-2 Level 3 requirements, which is the correct choice when hardware-backed key protection is mandated.
Quick reference
Symmetric Encryption Algorithm Comparison
| Algorithm | Key Size | Block Size | Status | Notes |
|---|---|---|---|---|
| AES-128 | 128-bit | 128-bit | Current standard | NIST approved; WPA3, TLS |
| AES-256 | 256-bit | 128-bit | Current standard | Preferred for sensitive / govt data |
| 3DES | 112-bit effective | 64-bit | Deprecated (2023) | Replaced by AES |
| DES | 56-bit | 64-bit | Broken | Cracked in < 24 h; never deploy |
| ChaCha20 | 256-bit | Stream cipher | Current | TLS 1.3, WireGuard |
Go deeper
Related to this question
Learn chapter
Google Kubernetes Engine (GKE)
Key term
BigQuery
BigQuery is a fully managed, serverless data warehouse on Google Cloud that lets you run fast SQL queries on massive datasets without managing any infrastructure.
Key term
Data
Data is raw, unprocessed information, like numbers, words, or measurements, that can be stored, processed, and analyzed by computers.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCA 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 PCA exam.