hardMultiple ChoiceObjective-mapped
CCSP Practice Question: A cloud service provider (CSP) is designing a…
A cloud service provider (CSP) is designing a multi-tenant infrastructure and needs to ensure that a security incident in one tenant's environment does not compromise the confidentiality or integrity of other tenants. The CSP plans to use a combination of network segmentation, hypervisor isolation, and encryption. Which additional control is MOST critical to prevent side-channel attacks that could leak cryptographic keys or other sensitive data across tenants?
⚠ Common exam trap
ISC2 often tests the distinction between network-level isolation (VLANs, firewalls) and microarchitectural side-channel defenses, leading candidates to choose network controls when the question specifically targets side-channel attacks that bypass network segmentation.
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
✓
Ensure cryptographic operations use constant-time algorithms.
Side-channel attacks, such as timing attacks, exploit variations in execution time to infer sensitive data like cryptographic keys. Constant-time algorithms ensure that cryptographic operations execute in a fixed duration regardless of input, eliminating timing variations that could be measured across shared physical hardware. This is critical in multi-tenant environments where tenants share CPU caches and memory buses, as it prevents an attacker from extracting key material through precise timing measurements.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Ensure cryptographic operations use constant-time algorithms.
Why this is correct
Constant-time algorithms resist timing and cache-based side-channel attacks.
- ✗
Implement virtual LANs (VLANs) and firewall rules between tenants.
Why it's wrong here
Network controls do not prevent side-channel attacks at the processor level.
- ✗
Use hardware security modules (HSMs) for key management.
Why it's wrong here
HSMs protect key storage but not execution side channels.
- ✗
Enforce strict API rate limiting for each tenant.
Why it's wrong here
Rate limiting does not mitigate side-channel vulnerabilities.
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
About these practice questions
One of 964 original CCSP practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.