SSCP Cryptography Practice Question
A security analyst is reviewing a digital signature implementation. The signer uses their private key to encrypt the hash of a message. What does the recipient use to verify the signature?
⚠ Common exam trap
Candidates often confuse the roles of keys in digital signatures, mistakenly thinking the recipient uses their own private key or the signer's private key for verification. In asymmetric cryptography, signature verification always uses the signer's public key.
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
✓
The signer's public key
Digital signatures use asymmetric cryptography where the signer encrypts the message hash with their private key. The recipient decrypts that encrypted hash using the signer's public key, then compares it to a locally computed hash of the received message. If they match, the signature is verified, proving both authenticity and integrity.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The recipient's private key
Why it's wrong here
The recipient's private key is used for decrypting messages sent to the recipient.
- ✗
The signer's private key
Why it's wrong here
The signer's private key is kept secret and used only for signing.
- ✗
The recipient's public key
Why it's wrong here
The recipient's public key is used for encrypting messages to the recipient, not for verifying signatures.
- ✓
The signer's public key
Why this is correct
The signer's public key is used to verify the signature by decrypting the hash.
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 SSCP practice question is part of Courseiva's free ISC2 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 SSCP exam.