Pseudonymization

The processing of personal data in such a manner that the data can no longer be attributed to a specific data subject without the use of additional information, provided that such additional information is kept separately and subject to technical and organizational measures. Under GDPR Article 4(5), pseudonymization involves replacing identifying fields with artificial identifiers or pseudonyms (such as replacing names with random ID numbers) while retaining the ability to re-identify individuals when necessary by using the separately stored mapping. Pseudonymized data remains personal data under GDPR because re-identification is possible, unlike anonymized data which is no longer personal data. However, pseudonymization is recognized as an important security measure and data protection safeguard (Article 32(1)(a)) that reduces privacy risks. It allows organizations to process data for legitimate purposes while limiting identifiability. Pseudonymization is particularly valuable for analytics, testing, research, and situations where direct identifiers aren't needed for the processing purpose but re-identification may occasionally be necessary.