“Pseudonymisation is increasingly becoming a key security technique for providing a means that can facilitate personal data processing, while offering strong safeguards for the protection of personal data and thereby safeguarding the rights and freedoms of individuals. Complementing previous work by ENISA, this report demonstrates how pseudonymisation can be deployed in practice to further promote the protection of health data during processing.”
https://www.enisa.europa.eu/publications/deploying-pseudonymisation-techniques