CAS-004 Security Engineering Practice Question
An organization wants to implement passwordless authentication for its employees using FIDO2/WebAuthn. What is a primary security advantage of this approach over traditional password-based MFA?
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 is resistant to phishing attacks because credentials are bound to the origin.
FIDO2 uses public key cryptography; the private key never leaves the user's device, so phishing attacks cannot steal credentials. This provides strong resistance to phishing.
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 is resistant to phishing attacks because credentials are bound to the origin.
Why this is correct
WebAuthn credentials are scoped to the relying party, so they cannot be used on fake sites.
- ✗
It eliminates the need for a second factor.
Why it's wrong here
FIDO2 itself is a multi-factor authentication (possession + biometric/PIN).
- ✗
It allows users to reuse the same credential across multiple websites.
Why it's wrong here
Credentials are origin-specific; reuse would be insecure.
- ✗
It does not require any client-side hardware.
Why it's wrong here
FIDO2 requires a platform authenticator (e.g., secure enclave) or external hardware token.
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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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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