CISSP Communication and Network Security Practice Question
This CISSP practice question tests your understanding of communication and network security. 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.
Which TWO options are valid methods for providing confidentiality in network communications? (Choose two.)
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
ESP in transport mode
ESP (Encapsulating Security Payload) in transport mode provides confidentiality by encrypting the payload of an IP packet while leaving the original IP header intact. This is a core function of IPsec, where ESP can optionally include authentication but its primary role is encryption, making it a valid method for ensuring data confidentiality in network communications.
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.
✗
SSH
Why it's wrong here
SSH provides encryption for remote sessions, but it is a terminal protocol, not a general network security protocol like IPsec or TLS.
✓
ESP in transport mode
Why this is correct
ESP provides encryption, thus confidentiality.
Related concept
Read the scenario before looking for a memorised answer.
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HMAC
Why it's wrong here
HMAC provides integrity and authentication, not confidentiality.
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AH in tunnel mode
Why it's wrong here
AH does not encrypt; it only provides authentication and integrity.
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
ISC2 often tests the distinction between protocols that provide confidentiality (encryption) versus those that provide integrity/authentication only, so candidates may mistakenly select AH or HMAC thinking they offer encryption when they do not.
Detailed technical explanation
How to think about this question
ESP in transport mode encrypts only the transport layer segment (e.g., TCP/UDP header and payload) and not the original IP header, which is useful for host-to-host communications where the IP header must remain visible for routing. TLS 1.3, defined in RFC 8446, provides confidentiality by encrypting the handshake and application data using symmetric encryption (e.g., AES-GCM) after a key exchange, and it eliminates obsolete features like static RSA key exchange to improve security. In real-world scenarios, ESP transport mode is often used in VPNs for site-to-site or remote access, while TLS 1.3 secures web traffic (HTTPS) and other application-layer protocols.
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.
Communication and Network Security — This question tests Communication and Network Security — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: ESP in transport mode — ESP (Encapsulating Security Payload) in transport mode provides confidentiality by encrypting the payload of an IP packet while leaving the original IP header intact. This is a core function of IPsec, where ESP can optionally include authentication but its primary role is encryption, making it a valid method for ensuring data confidentiality in network communications.
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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