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SSCP Practice Question: Which THREE of the following are common use cases…
Which THREE of the following are common use cases for public key infrastructure (PKI)? (Select exactly three.)
⚠ Common exam trap
Many candidates confuse the mechanism (e.g., using PKI to exchange a symmetric key) with a direct use case of PKI, or mistakenly think password hashing involves certificates, when PKI is specifically about public key certificates, not symmetric key exchange or hashing algorithms.
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
✓
Digital signatures
Digital signatures are a core use case for PKI because they rely on asymmetric cryptography where a private key signs data and the corresponding public key, bound to an identity via a digital certificate issued by a Certificate Authority (CA), verifies the signature. This ensures authenticity, integrity, and non-repudiation of the signed message or document.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Password hashing
Why it's wrong here
Password hashing uses hash functions, not PKI.
- ✗
Symmetric key exchange
Why it's wrong here
Symmetric key exchange is often done via algorithms like Diffie-Hellman, not directly PKI.
- ✓
Digital signatures
Why this is correct
PKI enables digital signatures using certificates.
- ✓
Email encryption (S/MIME)
Why this is correct
S/MIME uses PKI for email encryption and signing.
- ✓
SSL/TLS certificate authentication
Why this is correct
PKI provides the certificates for SSL/TLS authentication.
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 |
Go deeper
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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.