mediumMultiple ChoiceObjective-mapped
Designing Cloud Storage with Customer-Managed Keys and Granular Access
An organization is designing a cloud storage solution for highly sensitive customer data. The data must be encrypted at rest and the encryption keys must be managed by the customer, not the cloud provider. Additionally, the solution must allow granular access control based on data classification. Which combination of services should the architect recommend?
Quick Answer
The answer is a combination of Cloud HSM for key management and a cloud storage service with object-level ACLs. This is correct because Cloud HSM ensures customer-managed encryption keys for data at rest, giving the organization sole custody and control over the cryptographic material, which directly addresses the requirement that the cloud provider cannot access the keys. Pairing this with object-level ACLs enables granular access control, allowing permissions to be set per data classification level rather than broad bucket policies. On the Certified Cloud Security Professional CCSP exam, this scenario tests your understanding of the shared responsibility model and the distinction between provider-managed and customer-managed keys—a common trap is assuming server-side encryption with provider keys is sufficient. Remember the memory tip: “HSM for keys, ACLs for access” to quickly recall that key sovereignty and fine-grained permissions must come from separate, complementary services.
⚠ Common exam trap
ISC2 often tests the distinction between server-side encryption (where the provider performs encryption) and client-side encryption (where the customer encrypts before upload), and the trap here is assuming that server-side encryption with customer-managed keys (Option A) gives the customer full control over key management, when in fact the provider still has access to the keys during encryption/decryption operations.
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 HSM for key management and a cloud storage service with object-level ACLs.
Cloud HSM provides customer-managed keys for encryption at rest, ensuring the customer retains sole control over the keys. Combined with a cloud storage service that supports object-level ACLs, this allows granular access control based on data classification, meeting both requirements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Server-side encryption with customer-managed keys and a storage bucket with bucket-level policies.
Why it's wrong here
Bucket-level policies lack granular access control based on data classification.
- ✗
Server-side encryption with cloud-managed keys and a storage bucket with bucket-level policies.
Why it's wrong here
Keys are not customer-managed, and bucket policies are not granular.
- ✓
Cloud HSM for key management and a cloud storage service with object-level ACLs.
Why this is correct
Customer-managed keys in HSM and object-level ACLs meet both requirements.
- ✗
Client-side encryption with a cloud KMS and a storage bucket with bucket-level policies.
Why it's wrong here
Cloud KMS still involves cloud management of keys, and bucket policies are not granular.
Go deeper
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Same concept, more angles
1 more way this is tested on CCSP
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. Which TWO of the following are valid methods for securing data at rest in a cloud storage service?
easy- A.Disabling encryption to reduce latency.
- ✓ B.Implementing client-side encryption before uploading data.
- ✓ C.Using server-side encryption with customer-managed keys.
- D.Setting the storage bucket to public read access.
- E.Enabling access logging for the storage bucket.
Why B: Client-side encryption ensures data is encrypted before it leaves the client environment, so the cloud provider never has access to the plaintext. This is a valid method for securing data at rest in cloud storage, as the encrypted objects are stored in the service and can only be decrypted by the client holding the keys.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CCSP practice question is part of Courseiva's free ISC2 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 CCSP exam.