CAS-004 Security Architecture Practice Question
A financial services company is designing a hybrid cloud environment. The security architect must ensure that data in transit between the on-premises data center and the cloud provider is protected against interception and that the cloud provider cannot read the data. The company also needs to meet strict compliance requirements for key management. Which of the following should the architect implement to BEST meet these requirements?
⚠ Common exam trap
The trap here is assuming that any encryption in transit is sufficient, without considering who controls the encryption 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
✓
Deploy a customer-managed VPN gateway with hardware security modules (HSMs) for key storage and use IPsec with customer-managed certificates.
The requirement is to protect data in transit from interception and ensure the cloud provider cannot read it, while meeting strict key management compliance. A customer-managed VPN gateway with HSMs and customer-managed certificates ensures that encryption keys are controlled by the company, not the provider. IPsec provides strong encryption, and HSMs offer secure key storage, satisfying both security and compliance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement a dedicated AWS Direct Connect connection with MACsec encryption.
Why it's wrong here
AWS Direct Connect with MACsec provides encryption at the data link layer between the customer premises and the AWS Direct Connect location. However, MACsec keys are managed by the network equipment and may not provide end-to-end encryption to the cloud workload. The cloud provider could still access data within its network, and this does not satisfy the requirement that the provider cannot read the data.
- ✗
Use TLS 1.3 with mutual authentication for all data transfers and store private keys in a cloud-based key management service.
Why it's wrong here
TLS 1.3 with mutual authentication encrypts data in transit, but storing private keys in a cloud-based key management service means the cloud provider manages the keys. This violates the requirement that the provider cannot read the data. While TLS 1.3 is secure, the key management aspect fails to meet the compliance and confidentiality needs.
- ✗
Configure a site-to-site VPN using IPsec with pre-shared keys managed by the cloud provider.
Why it's wrong here
IPsec VPN with provider-managed pre-shared keys encrypts data in transit, but the cloud provider manages the keys and could potentially access them. This does not meet the requirement that the cloud provider cannot read the data. Additionally, pre-shared keys are less secure than certificate-based authentication and do not provide the necessary key management controls for compliance.
- ✓
Deploy a customer-managed VPN gateway with hardware security modules (HSMs) for key storage and use IPsec with customer-managed certificates.
Why this is correct
This approach uses a customer-managed VPN gateway and HSMs to store keys, ensuring that the cloud provider does not have access to the encryption keys. IPsec with customer-managed certificates provides strong encryption and authentication. This meets the requirements for data confidentiality against the provider and compliance with strict key management controls.
Quick reference
VPN Protocol Comparison
| Protocol | Port | Encryption | Authentication | Use Case |
|---|---|---|---|---|
| IKEv2 / IPsec | UDP 500 / 4500 | AES-256 | Certificates / PSK | Site-to-site & remote access |
| SSL / TLS VPN | TCP 443 | TLS 1.3 | Certificates / MFA | Clientless remote access |
| L2TP / IPsec | UDP 1701 | AES (IPsec) | PSK / Certificates | Legacy remote access |
| WireGuard | UDP 51820 | ChaCha20 | Public keys | Modern high-performance VPN |
| PPTP | TCP 1723 | MPPE (weak) | MS-CHAPv2 | Legacy — avoid in production |
PPTP is considered insecure. IKEv2/IPsec and SSL VPN are the current recommended options.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This CAS-005 practice question is part of Courseiva's free CompTIA 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 CAS-005 exam.