Distributed Data Security in Digital Health: Self-Sovereign Identity, Access Control, and Blockchain-based Log Records

The expansion of Digital Health brings increasing data privacy and security challenges, mainly due to data collection by service providers and third parties. The decentralized approach of Self-Sovereign Identity emerges as a solution, offering users direct control over their data. This paper proposes the SmartMed system for controlling access to private medical data by attribute-based access control implemented on smart contracts. The paper investigates the performance limitations of the Ethereum and Besu blockchain platforms in controlling access to medical data. The proposal develops smart contracts to perform attribute-based access control and to store log records in the blockchain, highlighting the detailed performance analysis on both tested platforms. The results reveal the superiority of the Besu platform over Ethereum, indicating a lower computational cost per transaction. Our proposal innovates by proposing a system based on smart contracts to guarantee the authenticity of medical data, complemented by the use of Keycloak in managing access to healthcare systems.