- A
Hardware random number generator (HRNG)
HRNGs provide high-quality entropy suitable for key generation.
- B
Random numbers from a website
Why wrong: External sources may be compromised or unreliable.
- C
Linear congruential generator (LCG)
Why wrong: LCGs are predictable and not cryptographically secure.
- D
Pseudorandom number generator (PRNG) seeded with current timestamp
Why wrong: Timestamps are predictable and not sufficient for cryptographic keys.
Question 537 of 1,000
SSCP Cryptography Practice Question
This SSCP practice question tests your understanding of cryptography. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
A company wants to implement a key management system. They need to generate cryptographic keys that are unpredictable. Which source of randomness should be used?
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
✓
Hardware random number generator (HRNG)
A hardware random number generator (HRNG) is the correct choice because it derives randomness from physical processes (e.g., thermal noise, quantum effects) that are inherently unpredictable and non-deterministic. Cryptographic key generation requires true entropy to resist brute-force and prediction attacks, which software-based deterministic methods cannot guarantee.
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.
- ✓
Hardware random number generator (HRNG)
Why this is correct
HRNGs provide high-quality entropy suitable for key generation.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Random numbers from a website
Why it's wrong here
External sources may be compromised or unreliable.
- ✗
Linear congruential generator (LCG)
Why it's wrong here
LCGs are predictable and not cryptographically secure.
- ✗
Pseudorandom number generator (PRNG) seeded with current timestamp
Why it's wrong here
Timestamps are predictable and not sufficient for cryptographic keys.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that a PRNG seeded with a timestamp is sufficient for cryptography, but the trap is that timestamps are predictable or guessable, making the output deterministic and insecure for key generation.
Detailed technical explanation
How to think about this question
HRNGs typically use analog circuits to amplify noise (e.g., Johnson–Nyquist noise) and then digitize it, often with post-processing like von Neumann debiasing to remove bias. In practice, many cryptographic modules (e.g., TPM 2.0, Intel RDRAND) combine an HRNG with a DRBG (deterministic random bit generator) to provide both entropy and high throughput, as specified in NIST SP 800-90A/B/C. A real-world scenario: generating an RSA key pair on a server without an HRNG could allow an attacker who knows the boot time to reconstruct the private key.
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.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
- →
Cryptography — study guide chapter
Learn the concepts, then practise the questions
- →
Cryptography practice questions
Targeted practice on this topic area only
- →
All SSCP questions
1,000 questions across all exam domains
- →
Systems Security Certified Practitioner SSCP study guide
Full concept coverage aligned to exam objectives
- →
SSCP practice test guide
How to use practice tests most effectively before exam day
Related practice questions
Related SSCP practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Access Controls practice questions
Practise SSCP questions linked to Access Controls.
Risk Identification, Monitoring, and Analysis practice questions
Practise SSCP questions linked to Risk Identification, Monitoring, and Analysis.
Incident Response and Recovery practice questions
Practise SSCP questions linked to Incident Response and Recovery.
Security Operations and Administration practice questions
Practise SSCP questions linked to Security Operations and Administration.
Cryptography practice questions
Practise SSCP questions linked to Cryptography.
Network and Communications Security practice questions
Practise SSCP questions linked to Network and Communications Security.
Systems and Application Security practice questions
Practise SSCP questions linked to Systems and Application Security.
Risk Identification, Monitoring and Analysis practice questions
Practise SSCP questions linked to Risk Identification, Monitoring and Analysis.
SSCP fundamentals practice questions
Practise SSCP questions linked to SSCP fundamentals.
SSCP scenario practice questions
Practise SSCP questions linked to SSCP scenario.
SSCP troubleshooting practice questions
Practise SSCP questions linked to SSCP troubleshooting.
Practice this exam
Start a free SSCP practice session
Short sessions build daily habit. Longer sessions build exam-day stamina. Try a timed session to simulate real conditions.
FAQ
Questions learners often ask
What does this SSCP question test?
Cryptography — This question tests Cryptography — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Hardware random number generator (HRNG) — A hardware random number generator (HRNG) is the correct choice because it derives randomness from physical processes (e.g., thermal noise, quantum effects) that are inherently unpredictable and non-deterministic. Cryptographic key generation requires true entropy to resist brute-force and prediction attacks, which software-based deterministic methods cannot guarantee.
What should I do if I get this SSCP 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.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
This SSCP 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 SSCP exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.