200-201 Security Concepts Practice Question

What is the primary difference between symmetric and asymmetric encryption?

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

✓

Symmetric uses a single shared key; asymmetric uses a key pair

Symmetric uses one shared key; asymmetric uses a public-private key pair.

Answer analysis

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

✗
Asymmetric encryption is used only for hashing
Why it's wrong here
Asymmetric is used for encryption and digital signatures, not hashing.
✗
Symmetric uses two keys, asymmetric uses one
Why it's wrong here
Symmetric uses one key; asymmetric uses two (public/private).
✗
Symmetric is slower than asymmetric
Why it's wrong here
Symmetric is generally faster than asymmetric.
✓
Symmetric uses a single shared key; asymmetric uses a key pair
Why this is correct
Correct: symmetric uses one key for both operations; asymmetric uses a public and private key.

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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