Which technique is a common method for de-identification in data exchanges?

• A. Masking
• B. Pseudonymization
• C. Aggregation
• D. Differential privacy

Answer: (A)

When sharing data, removing or concealing personal identifiers is essential to protect privacy. Masking directly hides identifiers like names, exact addresses, or full phone numbers, often replacing them with blanks, symbols, or partial values. This keeps the data’s structure intact and usable for testing, analytics, or integration, which is why masking is a common de-identification method in data exchanges.

Pseudonymization also hides identity by replacing identifiers with substitutes, but it relies on a separate key to re-identify if needed, which adds complexity and risk management considerations. Aggregation removes granularity by grouping data (for example, counts by category), which can obscure individuals but changes the level of detail. Differential privacy adds formal mathematical guarantees by injecting noise, offering strong protection but requiring more advanced implementation and resource trade-offs.