Pseudonymisation
Short definition
Pseudonymisation is the processing of personal data in such a way that they can no longer be attributed to a specific person without the use of additional information, kept separately and protected (GDPR, Article 4(5)).
In plain language
An example is replacing each service user's name with a code and keeping the lookup table in a separate place. It reduces risks, but pseudonymised data are still personal data and subject to the GDPR, because identification remains possible. It is widely used in clinical research. It should not be confused with anonymisation.