The correct combination is full-disk encryption and TLS for network communications. Full-disk encryption protects data at rest by encoding the entire storage drive, making it unreadable without the proper decryption key, while TLS encrypts data in transit by securing the communication channel between systems. On the ISC2 Certified in Cybersecurity CC exam, this question tests your ability to distinguish between encryption protocols and algorithms—a common trap is confusing AES (an algorithm) with a protocol like TLS, or selecting IPsec which only covers transit. Remember that “at rest” requires a storage-level control, and “in transit” requires a network-level protocol. A useful memory tip: “Rest needs a drive, transit needs a line”—full-disk encryption locks the drive, TLS secures the line.
ISC2 CC Security Principles Practice Question
This CC practice question tests your understanding of security principles. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. 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's security policy mandates that data must be encrypted both at rest and in transit. Which combination of controls meets this requirement?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Full-disk encryption and TLS for network communications
Option C is correct because full-disk encryption protects data at rest, and TLS encrypts data in transit. AES is an encryption algorithm, but not a protocol; IPsec encrypts in transit but not at rest. S/MIME is for email in transit, but doesn't cover other data. RBAC manages access, not encryption.
Key principle: NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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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AES encryption for files and IPsec for network traffic
Why it's wrong here
AES is an algorithm, not a full solution for data at rest; IPsec protects in transit but not at rest.
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BitLocker and EFS
Why it's wrong here
BitLocker is full-disk encryption (at rest) but EFS is file-level encryption; neither addresses data in transit.
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S/MIME for email and RBAC for file access
Why it's wrong here
S/MIME encrypts email in transit but not at rest; RBAC does not encrypt data.
✓
Full-disk encryption and TLS for network communications
Why this is correct
Full-disk encryption secures data at rest, and TLS secures data in transit.
Related concept
Static NAT maps one inside address to one outside address.
Common exam traps
Common exam trap: NAT rules depend on direction and matching traffic
NAT is not only about the public address. The inside/outside interface roles and the ACL or rule that matches traffic are just as important.
Detailed technical explanation
How to think about this question
NAT questions usually test address translation, overload/PAT behaviour, static mappings and whether the right traffic is being translated. Read the interface direction and address terms carefully.
KKey Concepts to Remember
Static NAT maps one inside address to one outside address.
PAT allows many inside hosts to share one public address using ports.
Inside local and inside global describe the private and translated addresses.
NAT ACLs identify traffic for translation, not always security filtering.
TExam Day Tips
→Identify inside and outside interfaces first.
→Check whether the scenario needs static NAT, dynamic NAT or PAT.
→Do not confuse NAT matching ACLs with normal packet-filtering intent.
Key takeaway
NAT direction and interface roles matter as much as the IP address mapping. Inside/outside designation controls which traffic is translated.
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 CC question in full detail.
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CC NAT questions on configuration and troubleshooting.
Security Principles — This question tests Security Principles — Static NAT maps one inside address to one outside address..
What is the correct answer to this question?
The correct answer is: Full-disk encryption and TLS for network communications — Option C is correct because full-disk encryption protects data at rest, and TLS encrypts data in transit. AES is an encryption algorithm, but not a protocol; IPsec encrypts in transit but not at rest. S/MIME is for email in transit, but doesn't cover other data. RBAC manages access, not encryption.
What should I do if I get this CC question wrong?
Review the four NAT address types (inside local, inside global, outside local, outside global), PAT port overload, and static vs dynamic NAT use cases. Then practise related CC NAT questions on configuration and troubleshooting.
What is the key concept behind this question?
Static NAT maps one inside address to one outside address.
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This CC 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 CC exam.
Question Discussion
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