A privacy engineer is working with a data science team that wants to use a production customer database for developing a churn prediction model. The database contains names, email addresses, and purchase histories. The team proposes to replace names and email addresses with random identifiers and store the mapping in a separate table. Which privacy engineering technique is being applied?
Trap 1: Anonymization
Anonymization irreversibly removes the ability to re-identify individuals. In this scenario, the mapping table is retained separately, so re-identification remains possible. Therefore, the data is not anonymized. Anonymization would require destroying the mapping and ensuring no other data can be used to single out individuals, which is not the case here.
Trap 2: Data masking
Data masking typically involves obfuscating data in a non-production environment, often irreversibly, but it does not necessarily preserve a mapping for re-identification. The scenario explicitly retains a mapping table, which is characteristic of pseudonymization, not masking. Masking might be used for test data, but here the goal is to enable analysis with the option to re-identify.
Trap 3: Tokenization
Tokenization replaces sensitive data with tokens that have no intrinsic meaning, and the mapping is stored in a token vault. While similar, tokenization is often used for payment card data and may not involve a separate mapping table managed by the data team. The scenario describes a simple mapping table, which is more indicative of pseudonymization than tokenization.
- A
Anonymization
Why it fails: Anonymization irreversibly removes the ability to re-identify individuals. In this scenario, the mapping table is retained separately, so re-identification remains possible. Therefore, the data is not anonymized. Anonymization would require destroying the mapping and ensuring no other data can be used to single out individuals, which is not the case here.
- B
Data masking
Why it fails: Data masking typically involves obfuscating data in a non-production environment, often irreversibly, but it does not necessarily preserve a mapping for re-identification. The scenario explicitly retains a mapping table, which is characteristic of pseudonymization, not masking. Masking might be used for test data, but here the goal is to enable analysis with the option to re-identify.
- C
Tokenization
Why it fails: Tokenization replaces sensitive data with tokens that have no intrinsic meaning, and the mapping is stored in a token vault. While similar, tokenization is often used for payment card data and may not involve a separate mapping table managed by the data team. The scenario describes a simple mapping table, which is more indicative of pseudonymization than tokenization.
- D
Pseudonymization
Pseudonymization replaces direct identifiers with artificial identifiers, and the mapping table allows re-identification. This aligns with the scenario where names and emails are replaced by random IDs and the mapping is kept separately. It reduces privacy risk while preserving data utility for model development, and is explicitly recognized as a privacy-enhancing technique under regulations such as the GDPR.