CAS-004 Security Engineering Practice Question

Which of the following is a primary advantage of using ChaCha20-Poly1305 over AES-256-GCM in certain environments?

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

✓

Faster performance on devices without AES-NI

ChaCha20-Poly1305 is designed to be faster in software that lacks AES hardware acceleration, making it suitable for mobile devices.

Answer analysis

For each option: why learners choose it and why it is or isn't the right answer here.

✗
Better hardware acceleration support
Why it's wrong here
AES has better hardware acceleration.
✗
Higher security margin
Why it's wrong here
Both are considered secure.
✗
Smaller ciphertext size
Why it's wrong here
Both produce similar sizes.
✓
Faster performance on devices without AES-NI
Why this is correct
ChaCha20 is optimized for software implementation.

Quick reference

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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