SPChain: Blockchain-based Medical Data Sharing and Privacy-preserving eHealth System

TL;DR

SPChain is a blockchain-based eHealth system that enhances security and privacy in medical data sharing by integrating novel cryptographic techniques and a new blockchain structure, enabling secure, efficient, and patient-controlled EMR sharing.

Contribution

The paper introduces SPChain, a novel blockchain system combining RepuCoin and SNARKs-based chameleon hash to resist attacks and improve privacy-preserving medical data sharing.

Findings

Resists 51% and other blockchain attacks.

Enables privacy-preserving EMR sharing among institutions.

Achieves high security and efficiency in performance evaluations.

Abstract

The development of eHealth systems has brought great convenience to people's life. Researchers have been combining new technologies to make eHealth systems work better for patients. The Blockchain-based eHealth system becomes popular because of its unique distributed tamper-resistant and privacy-preserving features. However, due to the security issues of the blockchain system, there are many security risks in eHealth systems utilizing the blockchain technology. i.e. 51% attacks can destroy blockchain-based systems. Besides, trivial transactions and frequent calls of smart contracts in the blockchain system bring additional costs and security risks to blockchain-based eHealth systems. Worse still, electronic medical records (EMRs) are controlled by medical institutions rather than patients, which causes privacy leakage issues. In this paper, we propose a medical data Sharing and Privacy-preserving eHealth system based on blockChain technology (SPChain). We combine RepuCoin with the SNARKs-based chameleon hash function to resist underlying blockchain attacks, and design a new chain structure to make microblocks contribute to the weight of blockchain. The system allows patients to share their EMRs among different medical institutions in a privacy-preserving way. Besides, authorized medical institutions can label wrong EMRs with the patients' permissions in the case of misdiagnosis. Security analysis and performance evaluation demonstrate that the proposed system can provide a strong security guarantee with a high efficiency.