Design principle DP1: Do not store personal data on a blockchain
Blockchain's paradigm of tamper-resistant storage jars profoundly with the right to rectification and erasure, so we encourage blockchain solution architects to keep personal data off-chain rather than relying on tampering approaches that would allow deletion of on-chain data, which would betray the idea of tamper-resistant storage. This design principle may encourage the creation of a B2B blockchain network that does not process personal data of either the network's participants or third parties.
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).