When discussing identification, a certain vocabulary of terms is necessary. To support precise statements, this subsection begins with some definitions of terms. It then presents a technical model for the GDPR-concept of identification. Finally, it presents transformations suited to reduce the identification-potential of personal data. The latter are used in both, pseudonymization and anonymization. They are often called “anonymization techniques”; but this is misleading, since they frequently fail to guarantee that the resulting data are indeed anonymous.