Unified access to anonymous records through a trustworthy system is needed in our increasingly globalised world that still suffers from profoundly disconnected health care services. Emergencies are followed by redundant, costly and slow medical examinations without a global health data sharing mechanism. We establish the foundations of a decentralised healthcare ledger where patients decide what to share, with who, and with minimal costs. We review the state-of-the-art of transparent, auditable and interactive Blockchain-based healthcare studies, developing ClinicAppChain. Our solution features authentication, confidentiality and permissioned data sharing, considering the EU data protection regulation of 2018. ClinicAppChain is a cross-platform low-cost Blockchain prototype that empowers patients, hospitals, researchers, pharmaceuticals and insurance industries without crypto-currencies involved, and with a negligible energy foot-print (7.7 watts per node).

Work by Munoz and Fuentes is supported by the projects MAGIC P12-TIC1814 and HADAS TIN2015-64841-R (co-financed by FEDER funds). Work by Constantinescu and Asenjo is supported by the project TIN2016-80920-R, funded by the Spanish Government. ClinicAppChain has been supported by IMFAHE Foundation-Nodal Award of 2018. We are particularly grateful to other members of the awarded team that have guided us in the sanitary side and legal aspects: Esther Herrera, Laura Timanfaya, Patricia Rodríguez and Myriam Martínez.