ISC Security Planning And Engineering Practice Question
During the design of a PKI hierarchy for a highly classified system, the ISSEP needs to ensure that the Root CA is kept offline. What is the most appropriate way to sign the Subordinate CA request?
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
✓
Transfer the CSR via air-gapped media to the offline Root CA, sign, and return the certificate.
To maintain an offline Root CA, the CSR from the Subordinate CA must be transferred via secure, out-of-band medium to the offline environment, signed, and the resulting certificate returned.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Expose the Root CA via a restricted management port in the firewall.
Why it's wrong here
Exposing management ports increases the risk of unauthorized access to the Root key.
- ✗
Configure a secure VPN tunnel between the Subordinate CA and the Root CA to exchange the CSR.
Why it's wrong here
A VPN tunnel implies the Root CA is online, which defeats the purpose of an offline Root.
- ✗
Use an HSM to automatically sign the request from the Subordinate CA.
Why it's wrong here
Automatic signing requires an online connection.
- ✓
Transfer the CSR via air-gapped media to the offline Root CA, sign, and return the certificate.
Why this is correct
This preserves the integrity of the Root CA by keeping it air-gapped.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed August 2026 · checked against the official (ISC)² exam blueprint
This ISC practice question is part of Courseiva's free (ISC)² 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 ISC exam.