Pseudonymization

Pseudonymization replaces direct identifiers, such as names, email addresses, or account numbers, with artificial values like random tokens or hashed strings. The mapping between the pseudonym and the real identity is stored separately under strict access controls. Without that mapping, the pseudonymized data cannot be traced back to an individual through reasonable effort.

The GDPR specifically references pseudonymization as a safeguard that can reduce risk to data subjects and may support compliance in areas like data minimization, security of processing, and lawful secondary use. However, pseudonymized data is still considered personal data under the regulation because re-identification remains possible with the additional information.

Pseudonymization differs from anonymization. Anonymized data is irreversibly stripped of identifying elements and falls outside the scope of data protection law. Pseudonymized data retains the possibility of re-identification and therefore remains regulated.

For CIAM, pseudonymization helps platforms protect customer identities in analytics, logs, and shared datasets while maintaining the ability to re-link data when operationally required.

Sources

• Regulation (EU) 2016/679 (GDPR): https://eur-lex.europa.eu/eli/reg/2016/679/oj