Blockchain-based privacy preserving e-health system for healthcare data in cloud

Cloud-assisted electronic health (e-health) system has played an important role in the management of healthcare data, which can provide efficient and convenient storage services for the patients to store their electronic health records (EHRs). However, there are the security challenges in the existing e-health system, where the malicious doctors may collude with cloud storage service provider (CSP) to tamper with the patients’ EHRs, or directly reveal the content of EHRs to other adversaries for profit. In this paper, we propose a blockchain-based privacy preserving e-health system to ensure the security and confidentiality of the patients’ EHRs. In the system, we introduce the pairing-based cryptography to generate the tamper-proof records of the EHRs and allow the patients to integrate them into the transactions deployed on the blockchain, which can make the patients’ EHRs verifiable and protect them from illegal modification. Moreover, we will design secure payment protocols by performing blockchain-based smart contracts, which can enable the patients and hospital to reliably pay for the diagnostic and storage service, respectively. Security analysis and the performance evaluation demonstrate that our proposed scheme is secure and efficient with a limited computation overhead.