hardMultiple ChoiceObjective-mapped
CISSP Practice Question: Deploying a new application that processes…
A company is deploying a new application that processes personally identifiable information (PII) in a hybrid cloud environment. The security architect needs to ensure that encryption keys are never exposed to the cloud provider. Which solution should be recommended?
⚠ Common exam trap
A common mix-up: candidates confuse 'customer-provided keys' (SSE-C) with 'client-side encryption' — SSE-C still sends the key to the cloud provider for each operation, while client-side encryption keeps the key entirely on-premises.
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
✓
Client-side encryption with keys stored on-premises
Client-side encryption ensures that encryption keys are generated and managed on-premises, never transmitted to the cloud provider. This directly meets the requirement that keys are never exposed to the cloud provider, as all cryptographic operations occur before data leaves the customer's controlled environment.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Envelope encryption with a key management service
Why it's wrong here
Envelope encryption with a cloud Key Management Service (KMS) means that while data is encrypted with a data encryption key (DEK) and the DEK is encrypted with a key encryption key (KEK), both the DEK and KEK are managed within the cloud provider's infrastructure. Although the KMS offers robust security controls and hardware security modules, the cloud provider ultimately maintains control over the keys. This setup does not meet the requirement of keeping keys entirely out of the cloud provider's reach, as the provider still has access to or control over the cryptographic material.
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Server-side encryption with cloud provider managed keys
Why it's wrong here
Server-side encryption with cloud provider managed keys implies that the cloud provider is responsible for generating, storing, and managing all encryption keys. The customer has no direct control over these keys, and they reside entirely within the cloud provider's environment, making the customer dependent on the provider's security practices for key protection. This approach, while convenient, introduces a significant trust dependency on the cloud provider for key security and access, which is unsuitable when maximum customer control over sensitive data encryption keys is paramount.
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Client-side encryption with keys stored on-premises
Why this is correct
Client-side encryption with keys stored on-premises ensures that data is encrypted by the customer's application before it is ever transmitted to or stored in the cloud. The encryption keys are generated, stored, and managed exclusively within the customer's secure on-premises environment, never being exposed to the cloud provider. This architecture provides the strongest assurance of data confidentiality and integrity, as the cloud provider only ever receives encrypted data and possesses no means to decrypt it, thereby maintaining complete customer control over sensitive information.
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Server-side encryption with customer-provided keys
Why it's wrong here
Server-side encryption with customer-provided keys (SSE-C) requires the customer to supply the encryption key to the cloud service each time data needs to be encrypted or decrypted. While the customer generates and manages the key, it must be transmitted to the cloud provider, even if temporarily and over a secure channel, for the encryption or decryption operation to occur. This momentary exposure of the key to the cloud environment, even in transit or memory, introduces a potential risk and means the cloud provider is not entirely 'key-blind,' failing to meet the highest standard of key isolation.
Go deeper
Related to this question
Learn chapter
Security Governance and Principles
Key term
Encryption
Encryption is the process of converting readable data into a secret code to prevent unauthorized access.
Key term
Security
Security in IT is the practice of protecting systems, networks, and data from unauthorized access, damage, or theft.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISSP 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 CISSP exam.