Pseudonymization is „the processing of personal data in such a way 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 is subject to technical and organizational measures to ensure that the personal data cannot be attributed to an identified or identifiable natural person“ (BlnDSG §31, 2020; EU GDPR Article 4 No. 5, 2016).