200-201 Security Concepts Practice Question
An organization wants to ensure that a user cannot deny having sent an email. Which security goal does this address?
⚠ Common exam trap
Cisco often tests the distinction between integrity and non-repudiation, where candidates mistakenly choose integrity because they associate hashing with proof of origin, but integrity alone does not link the data to a specific sender.
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
✓
Non-repudiation
Non-repudiation ensures that a party cannot deny having performed a specific action, such as sending an email. This is typically achieved through digital signatures using asymmetric cryptography (e.g., RSA or ECDSA) and public key infrastructure (PKI), where the sender's private key creates a signature that can be verified by anyone with the sender's public key. The goal is to provide irrefutable proof of origin and integrity, preventing the sender from later claiming they did not send the message.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Non-repudiation
Why this is correct
Non-repudiation provides cryptographic proof of origin through digital signatures, binding the sender's identity to the message so they cannot later deny sending it. This directly satisfies the scenario's requirement that a user cannot deny having sent an email, unlike confidentiality, integrity or availability goals.
- ✗
Availability
Why it's wrong here
Availability concerns ensuring systems and data remain accessible to authorised users, which does not address preventing a sender from denying an email. It is tempting because email delivery depends on uptime, and would be correct if the requirement were guaranteeing mailbox or service access during outages.
- ✗
Integrity
Why it's wrong here
Integrity guarantees data has not been altered, but non-repudiation additionally binds the sender's identity to the message through digital signatures. It is tempting because both rely on hashing and signing, and would be correct if the requirement were detecting tampering rather than proving who sent it.
- ✗
Confidentiality
Why it's wrong here
Confidentiality ensures data is readable only by authorised parties, typically through encryption, and does not prevent a sender from denying authorship. It is tempting because email security often involves encryption, and would be correct if the requirement were protecting message contents from unauthorised disclosure.
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 200-201 practice question is part of Courseiva's free Cisco 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 200-201 exam.