CAS-004 Security Engineering Practice Question
An organization is moving to a passwordless authentication approach. They require a solution that supports hardware-based cryptographic authentication and is resistant to phishing. Which standard should they implement?
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
✓
FIDO2/WebAuthn
FIDO2/WebAuthn uses public-key cryptography and hardware authenticators to provide phishing-resistant, passwordless authentication. TOTP is not passwordless and can be phished.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
TOTP (Time-based One-Time Password)
Why it's wrong here
TOTP still requires a seed and is susceptible to phishing.
- ✗
SMS-based one-time codes
Why it's wrong here
SMS is vulnerable to SIM swapping and phishing.
- ✓
FIDO2/WebAuthn
Why this is correct
FIDO2 uses public-key cryptography and hardware authenticators, providing phishing resistance.
- ✗
Password manager with autofill
Why it's wrong here
Password managers still rely on passwords and can be phished.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
Go deeper
Related to this question
About these practice questions
One of 968 original CAS-005 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
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.