CAS-004 Security Engineering Practice Question
A company is implementing a passwordless authentication solution using FIDO2/WebAuthn. What is the primary security advantage of this approach over traditional password-based authentication?
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
✓
It prevents phishing attacks by using cryptographic keys.
FIDO2 uses public key cryptography, so private keys never leave the device, preventing credential theft.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
It allows users to share passwords securely.
Why it's wrong here
Passwordless does not involve sharing passwords.
- ✗
It reduces server storage requirements.
Why it's wrong here
Server stores public keys, not passwords, but storage is not the primary advantage.
- ✗
It eliminates the need for multi-factor authentication.
Why it's wrong here
FIDO2 is itself a form of MFA.
- ✓
It prevents phishing attacks by using cryptographic keys.
Why this is correct
FIDO2's origin-bound keys prevent phishing.
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 |
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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.