EDPB Guidelines on blockchain (v2.0)

Guidelines 02/2025 on processing of personal data through blockchain technologies

The guidelines, adopted in final version following public consultation, analyse how blockchain's technical properties interact with GDPR data protection principles, covering the allocation of controller and processor roles among blockchain participants, and the specific challenges blockchain poses for purpose limitation, data minimisation, accuracy, and storage limitation given its append-only, tamper-resistant design. They set out technical measures — including encryption, hashing, and cryptographic commitments — to mitigate risks of storing personal data on-chain, and address how the rights to erasure, rectification, and objection can be implemented despite blockchain's technical constraints.