easyMultiple ChoiceObjective-mapped
CISA Practice Question: A small business wants to protect customer data…
A small business wants to protect customer data collected through its e-commerce website. Which control is most appropriate for protecting the data at rest and in transit?
⚠ Common exam trap
It's easy for candidates to confuse preventive controls like firewalls or IDS with data protection mechanisms, failing to recognize that encryption is the only direct safeguard for data confidentiality both at rest and in transit.
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
✓
Use encryption for data at rest and in transit.
Encryption is the only control that directly protects the confidentiality and integrity of data both at rest (e.g., AES-256 for database files) and in transit (e.g., TLS 1.3 for HTTPS). It renders data unreadable without the proper decryption key, ensuring that even if storage media or network traffic is intercepted, the customer data remains secure.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Implement a network firewall to block unauthorized access.
Why it's wrong here
Firewalls protect the network perimeter but do not encrypt data, so they are insufficient for protecting data at rest and in transit.
- ✗
Perform regular backups of the database to ensure data availability.
Why it's wrong here
Backups ensure data can be restored but do not protect confidentiality or prevent unauthorized access.
- ✗
Deploy an intrusion detection system (IDS) to monitor for threats.
Why it's wrong here
IDS detects potential attacks but does not protect data confidentiality or encrypt it.
- ✓
Use encryption for data at rest and in transit.
Why this is correct
Encryption directly protects data confidentiality by making it unreadable without the decryption key, applicable both at rest and in transit.
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 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.