JMIR Publications

ABSTRACT

Background:

Blockchain has the potential to disrupt the current modes of patient data access, accumulation, contribution, exchange, and control. Using interoperability standards, smart contracts, and cryptographic identities, patients can securely exchange data with providers and regulate access. The resulting comprehensive, longitudinal medical records can significantly improve the cost and quality of patient care for individuals and populations alike.

Objective:

This work presents HealthChain, a novel patient-centered blockchain framework. The intent is to bolster patient engagement, data curation, and regulated dissemination of accumulated information in a secure, interoperable environment. A mixed-block blockchain is proposed to support immutable logging and redactable patient blocks. Patient data are generated and exchanged via HL7 FHIR, allowing seamless transfer with compliant systems. Additionally, patients receive cryptographic identities in the form of public/private key pairs. Public keys are stored in the blockchain and are suitable for securing and verifying transactions. Furthermore, the envisaged system utilizes proxy re-encryption to share information via revocable, smart contracts, ensuring the preservation of privacy and confidentiality. Finally, several proxy re-encryption improvements are offered to enhance performance and security.

Methods:

The framework was formulated to address key barriers to blockchain adoption in health care, namely: information security, interoperability, data integrity, identity validation, and scalability. It supports sixteen configurations through the manipulation of four modes. An open-source, proof-of-concept tool was developed to evaluate the performance of the novel patient block components and system configurations. To demonstrate the utility of the proposed framework and evaluate resource consumption, extensive testing was performed on each of the sixteen configurations over a variety of scenarios involving a variable number of existing and imported records.

Results:

The results indicate several clear high-performing, low-bandwidth configurations, though they are not the strongest cryptographically. Of the strongest models, one’s anticipated cumulative record size is shown to influence the selection. While the most efficient algorithm is ultimately user-specific, AES-encrypted data with static keys, incremental server storage, and no additional server-side encryption is the fastest and least bandwidth intensive, while proxy re-encrypted data with dynamic keys, incremental server storage, and additional server-side encryption is the best performing of the strongest configurations.

Conclusions:

Blockchain is a potent and viable technology for patient-centered access to and exchange of health information. By integrating a structured, interoperable design with patient-accumulated and generated data shared via smart contracts into a universally accessible blockchain, HealthChain presents patients and providers with access to consistent and comprehensive medical records. Challenges addressed include data security, interoperability, block storage, and patient-administered data access, with several configurations emerging for further consideration regarding speed and security.