Drag a concept onto its matching description — or click a concept then click the description.
Concepts
Matches
Same key for encrypt and decrypt
Public/private key pair
Temporary key for a session
Kept secret by owner
mediumMatchingObjective-mapped
CISA Match each encryption key type to its usage. Practice Question
Match each encryption key type to its usage.
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 key: Used for bulk encryption and decryption with the same key
Symmetric keys are used for bulk encryption with a shared key, while public keys are distributed for encryption/verification. Asymmetric keys involve a key pair and are not optimized for bulk encryption; private keys must be kept secret for decryption/signing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Symmetric key: Used for bulk encryption and decryption with the same key
Why this is correct
Symmetric key encryption uses the same key for both encryption and decryption, making it efficient for large data.
- ✓
Public key: Used to encrypt data or verify signatures; can be shared openly
Why this is correct
Public keys are distributed openly and used for encryption or signature verification.
- ✗
Asymmetric key: Used for encrypting large amounts of data quickly
Why it's wrong here
Incorrect — large data encryption uses symmetric keys due to performance; asymmetric keys are for key exchange and signatures.
- ✗
Private key: Used to encrypt data that will be decrypted with a public key
Why it's wrong here
Incorrect — private keys are used for decryption or signing, not for encrypting data that will be decrypted with a public key.
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 CISA practice question is part of Courseiva's free ISACA 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 CISA exam.