hardMultiple ChoiceObjective-mapped
CISA Practice Question: Migrating its customer database to a public cloud…
A company is migrating its customer database to a public cloud provider. Which of the following encryption strategies best protects data while minimizing performance impact on queries?
⚠ Common exam trap
Many exam-takers assume full-database encryption (Option A) is the most secure and thus the best choice, overlooking the critical requirement to minimize performance impact on queries, which column-level encryption and tokenization directly address by avoiding unnecessary decryption of non-sensitive data.
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 column-level encryption and tokenization for sensitive fields.
Column-level encryption and tokenization allow sensitive fields (e.g., SSNs, credit card numbers) to be protected while leaving non-sensitive columns unencrypted, preserving query performance on indexed and frequently queried data. Tokenization replaces sensitive values with non-sensitive placeholders, enabling joins and lookups without decryption overhead, and column-level encryption limits decryption to only the required fields per query.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Encrypt the entire database at rest using AES-256, and decrypt for each query.
Why it's wrong here
Full database decryption for each query would cause significant performance degradation.
- ✗
Encrypt the database at the application layer before storage.
Why it's wrong here
Application-layer encryption would require decryption for any query, impacting performance and functionality.
- ✓
Use column-level encryption and tokenization for sensitive fields.
Why this is correct
Correct. This minimizes performance impact by encrypting only sensitive columns and using tokens for efficient lookups.
- ✗
Rely on the cloud provider's default encryption for the storage.
Why it's wrong here
Default encryption may not provide granular control and could still cause performance issues if the entire database is encrypted.
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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.