CISSP Asset Security Practice Question
A company is designing a database that will contain personally identifiable information (PII). To reduce privacy risk, they decide to add controlled noise to query results. This technique is known as:
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
✓
Differential privacy
Differential privacy adds noise to query outputs to protect individual privacy while allowing aggregate analysis.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Data masking
Why it's wrong here
Data masking involves replacing sensitive, real data with realistic but fictitious data, typically for non-production environments like testing, development, or training. While it preserves the data's format and referential integrity, allowing applications to function correctly, its primary purpose is to prevent the exposure of actual sensitive information rather than to enable privacy-preserving statistical analysis through noise injection. It focuses on substitution to create safe copies, not on mathematically guaranteed privacy for aggregate queries.
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Tokenization
Why it's wrong here
Tokenization is the process of replacing sensitive data elements with non-sensitive substitutes, known as tokens, which are typically randomly generated values. These tokens bear no mathematical or algorithmic relationship to the original data, making it extremely difficult to reverse-engineer the original value from the token. This technique is primarily used to reduce the scope of compliance requirements, such as PCI DSS, by ensuring sensitive data is not stored or processed directly, but it does not involve adding noise for privacy-preserving analytics.
- ✓
Differential privacy
Why this is correct
Differential privacy is a rigorous mathematical framework that quantifies and limits the privacy risk to individuals when their data is part of a dataset used for statistical queries. It achieves this by strategically injecting calibrated noise into query results or the data itself, ensuring that the presence or absence of any single individual's data in the dataset does not significantly alter the output of an analysis. This allows for aggregate insights while providing strong, provable guarantees against re-identification, even by an attacker with auxiliary information.
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Anonymization
Why it's wrong here
Anonymization involves removing or obscuring direct and indirect identifiers from a dataset to prevent the re-identification of individuals. Techniques include generalization (e.g., replacing exact age with age range), suppression (removing specific records or fields), and pseudonymization (replacing direct identifiers with pseudonyms). While it reduces re-identification risk, traditional anonymization often sacrifices data utility and does not offer the strong, quantifiable privacy guarantees against sophisticated inference attacks that differential privacy provides through the addition of noise.
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Related to this question
Learn chapter
Asset Security: Privacy and Data Retention
Key term
Privacy
Privacy in IT is the control over how personal data is collected, stored, used, and shared by systems and organizations.
Key term
Risk
Risk is the possibility that an event or action will negatively affect an organization's ability to achieve its goals, often measured in terms of likelihood and impact.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This CISSP 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 CISSP exam.