CAS-004 Security Engineering Practice Question
An organization requires a cryptographic algorithm that provides both encryption and authentication in a single pass. Which algorithm should be selected?
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
✓
AES-256-GCM
AES-256-GCM is an authenticated encryption mode that provides both confidentiality and integrity in a single operation.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
AES-256-GCM
Why this is correct
GCM is an authenticated encryption mode that provides both encryption and integrity.
- ✗
AES-256-CBC
Why it's wrong here
CBC does not provide authentication.
- ✗
SHA-256
Why it's wrong here
SHA-256 is a hash function, not encryption.
- ✗
RSA 4096
Why it's wrong here
RSA is asymmetric encryption, not for bulk data and does not provide authentication in a single pass.
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.