Source: PDPC Guide to basic data anonymisation techniques
Adapted for non-commercial and educational purposes only
Controlling access and imposing restriction on access are ways to ensure that anyone who has access to the data agrees to not attempt to re-identify it.
Contracts and agreements are usually applied, on top of security measures.
This method can ensure that data is only used for legitimate purposes, and can significantly lower the risk of re-identification. However, overly draconian control may reduce the utility of the data.