The answer is server-side encryption with customer-provided keys, or SSE-C. This is the correct choice because SSE-C allows an organization to encrypt objects at rest in cloud storage using encryption keys that the customer manages and supplies with each API request, rather than relying on the cloud provider to generate or store the keys. On the CISSP exam, this concept tests your understanding of the shared responsibility model and the distinction between provider-managed and customer-managed encryption controls. A common trap is confusing SSE-C with SSE-S3 or SSE-KMS, where the cloud provider retains key management authority. Remember the key differentiator: with SSE-C, the customer provides the key in every request, and the service never stores it, giving the customer full lifecycle control. A useful memory tip is “C for Customer-Controlled Key.”
CISSP Security Architecture and Engineering Practice Question
This CISSP practice question tests your understanding of security architecture and engineering. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
An organization requires that all data stored in a cloud object storage service be encrypted at rest using customer-managed keys. Which encryption option should be implemented?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Server-side encryption with customer-provided keys (SSE-C)
SSE-C (Server-Side Encryption with Customer-Provided Keys) allows the organization to encrypt objects at rest in cloud object storage using keys that are managed and supplied by the customer, not the cloud provider. This meets the requirement for customer-managed keys because the encryption key is provided in each API request and is never stored by the service, giving the customer full control over key lifecycle and access.
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.
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Server-side encryption with Amazon S3 managed keys (SSE-S3)
Why it's wrong here
Incorrect. SSE-S3 uses keys managed by the cloud provider.
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Transport Layer Security (TLS)
Why it's wrong here
Incorrect. TLS is for data in transit, not at rest.
✓
Server-side encryption with customer-provided keys (SSE-C)
Why this is correct
Correct. SSE-C allows customer to provide the encryption key.
Related concept
Read the scenario before looking for a memorised answer.
✗
Client-side encryption
Why it's wrong here
Incorrect. Client-side encryption encrypts data before sending to cloud.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates confuse 'customer-managed keys' with 'client-side encryption,' but the question specifies encryption at rest within the cloud service, which requires a server-side encryption option where the customer provides the key (SSE-C), not encryption performed before upload.
Detailed technical explanation
How to think about this question
With SSE-C, the customer includes the encryption key and its SHA-256 hash in the HTTP headers (e.g., x-amz-server-side-encryption-customer-key) for each PUT or GET request. The service uses the key to encrypt or decrypt the object in memory, then discards the key; the encrypted object is stored with a cryptographic hash of the key for integrity verification. This approach ensures that the cloud provider never has persistent access to the plaintext key, aligning with strict regulatory or compliance requirements for key ownership.
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 developer is choosing between AES-256 (symmetric) and RSA-2048 (asymmetric) for encrypting a large file that will be sent to a partner. Symmetric encryption is fast but requires key exchange; asymmetric is slower but solves the key distribution problem. A hybrid approach — encrypt the file with AES, encrypt the AES key with RSA — is standard. Questions like this test whether you understand when each approach applies.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this CISSP question in full detail.
Security Architecture and Engineering — This question tests Security Architecture and Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Server-side encryption with customer-provided keys (SSE-C) — SSE-C (Server-Side Encryption with Customer-Provided Keys) allows the organization to encrypt objects at rest in cloud object storage using keys that are managed and supplied by the customer, not the cloud provider. This meets the requirement for customer-managed keys because the encryption key is provided in each API request and is never stored by the service, giving the customer full control over key lifecycle and access.
What should I do if I get this CISSP question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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