What is pseudonymisation/de-identification of data?

Pseudonymisation/de-identification, just like anonymization of data, is intended to make it more difficult to draw a reference to a person from data. In this way, people’s PII can be protected. Here, data becomes a pseudonym (a code or ID number) through aliases. The link between the pseudonym and the original data set is stored in a master list. Accordingly, the personal reference can be re-established if access to this list is available.

Pseudonymization/de-identification of data is always useful if a reference to a person should be possible, but clear names should remain secret.