hardMultiple ChoiceObjective-mapped
ISC2 CC Practice Question: A security architect is designing a system that…
A security architect is designing a system that must ensure that a sender cannot later deny having sent a message. Which cryptographic mechanism should be implemented?
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 provide non-repudiation by binding the sender's identity to the message using public key cryptography. The sender cannot deny because only they possess the private key used to sign.
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 encryption
Why it's wrong here
Symmetric encryption does not provide non-repudiation as the shared key could be used by either party.
- ✗
Access control lists
Why it's wrong here
ACLs control who can access resources, not message non-repudiation.
- ✗
Hashing
Why it's wrong here
Hashing provides integrity but not non-repudiation; it does not tie the hash to a specific sender.
- ✓
Digital signatures
Why this is correct
Correct. Digital signatures ensure non-repudiation of origin.
Quick reference
Asymmetric Encryption Algorithm Comparison
| Algorithm | Key Exchange | Signatures | Equivalent Security Key | Notes |
|---|---|---|---|---|
| RSA-3072 | Yes | Yes | 128-bit | Widely deployed; slow for bulk data |
| ECDSA P-256 | No | Yes | 128-bit | Fast signatures; standard TLS certs |
| ECDH / ECDHE | Yes | No | 128-bit | Perfect forward secrecy in TLS 1.3 |
| DH / DHE | Yes | No | 128-bit (3072-bit key) | Replaced by ECDHE in modern TLS |
| Ed25519 | No | Yes | ~128-bit | SSH keys, modern PKI |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CC 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 CC exam.