Blockchain Tree for eHealth

Design of access control mechanisms for healthcare systems is challenging: it must strike the right balance between permissions and restrictions. In this work, we introduce a novel approach based on the Blockchain technology for storing patient medical data and creation an audit logging system able to protect health data from unauthorized modification and access. The proposed method has a tree structure: a main chain linked with patient's identity and one or several subchains used for storing additional critical data (e.g., medical diagnoses or access logs).