Design principle DP2: Use a highly secure off-chain mapping architecture for attribution
Certain use cases require that information propagated and stored on the blockchain can be attributed to a natural person. As Design Principle 1 also applies in these use cases, the information on the blockchain must not allow attribution without further information, and blockchain solution architects should employ a pseudonymization solution. The information required for attribution, such as a mapping of abstract blockchain IDs with specific IDs, has to remain off-chain and should be propagated using secure information channels. With such a solution, data controllers can rectify, through the propagation of rectification transactions, and they can erase, through the deletion of the information required for attribution.
Source paper
This design principle is proposed by How to Develop a GDPR-Compliant Blockchain Solution for Cross-Organizational Workflow Management: Evidence from the German Asylum Procedure (Florian Guggenmos, Annette Wenninger, Alexander Rieger, Gilbert Fridgen, Jannik Lockl, 2020).