The development of cloud-assisted electronic health system effectively addresses the
drawbacks of traditional medical management system. However, some challenging
problems such as security and privacy in data storage and sharing cannot be ignored. First,
it is difficult to ensure the integrity of electronic health records (EHRs) during the data
outsourcing process. Second, it is difficult to guarantee the privacy and traceability of EHRs
during the data sharing process. In this paper, a blockchain-based eHealth system called …