CAS-004 Security Architecture Practice Question
A company is preparing for post-quantum cryptography migration. According to NIST PQC standards, which algorithm is a candidate for key encapsulation?
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
✓
CRYSTALS-Kyber
CRYSTALS-Kyber is a NIST-selected algorithm for key encapsulation, designed to resist quantum attacks. It is used for establishing symmetric keys.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
CRYSTALS-Dilithium
Why it's wrong here
Dilithium is for digital signatures, not KEM.
- ✗
SPHINCS+
Why it's wrong here
SPHINCS+ is a stateless hash-based signature scheme.
- ✗
Falcon
Why it's wrong here
Falcon is also a digital signature algorithm.
- ✓
CRYSTALS-Kyber
Why this is correct
Kyber is the NIST standard for key encapsulation.
Quick reference
Symmetric Encryption Algorithm Comparison
| Algorithm | Key Size | Block Size | Status | Notes |
|---|---|---|---|---|
| AES-128 | 128-bit | 128-bit | Current standard | NIST approved; WPA3, TLS |
| AES-256 | 256-bit | 128-bit | Current standard | Preferred for sensitive / govt data |
| 3DES | 112-bit effective | 64-bit | Deprecated (2023) | Replaced by AES |
| DES | 56-bit | 64-bit | Broken | Cracked in < 24 h; never deploy |
| ChaCha20 | 256-bit | Stream cipher | Current | TLS 1.3, WireGuard |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.