# MedChain: Efficient Healthcare Data Sharing via Blockchain
## 6 Conclusions and Future Work  
Within the last decade, healthcare information exchange (HIE) technology has been widely discussed to facilitate patient diagnosis, R&D collaboration, and wellness improvement. Studies [48] have shown that HIE can benefit service providers in utilization increase, cost reduction, quality improvement, coordination of care, patient experience improvement, and disease surveillance. To provide patients with better control over their healthcare data and reduce information fragmentation, we proposed a patient-driven healthcare data-sharing framework, called MedChain. Compared with the existing blockchain-based approaches, our work has shown its higher efficiency in data sharing without a security compromise, through a dual-network architecture, a session-based data sharing scheme, and a digest chain structure. The result of the work is significant, since efficiency has been shown to be one of the top issues in healthcare blockchain adoption. Our experience suggests that a gradual integration and improvement of healthcare data sharing systems serves the interest of all parties. Healthcare providers are reluctant to migrate their systems and data to a new platform. Thus, in the preceding project [18], we integrated the new solution for inter-organizational data sharing with the legacy systems rather than totally discard them. MedChain extends this idea by developing a decentralized framework to attain more scalability without trusting a third party. Meanwhile, the scope of healthcare data is expanded by including data streams from various tracking devices, which can further help doctors and medical researchers. Thus, MedChain can maximize all parties' interest. The current version of MedChain contains some limitations and, thus, leaves the space for upgrade. Some of them have already been mentioned in previous sections. Here, we discuss other possible improvements. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Metrics** & **[28]** & **[30]** & **[31]** & **[32]** & **[33]** & **[34]** & **[35]** & **MedChain** \\ \hline Tamper-proof & Y & Y & Y & Y & Y & Y & Y & Y \\ Non-Repudiation & Y & Y & Y & Y & Y & Y & Y & Y \\ Attack Resistance & Y & Y & Y & Y & Y & Y & Y & Y \\ Access Control & N & N & Y & Y & Y & N & Y & Y \\ Access Revocation & N & N & Y & N & N & N & Y & Y \\ Privacy-Preserving & Y & N & N & N & N & Y & Y & Y \\ Block Search & N & N & N & N & Y & Y & Y & Y \\ Metadata Update & N & N & N & N & N & N & N & Y \\ Storage Space Recycling & N & N & N & N & N & N & N & Y \\ Data Stream Support & N & N & N & N & N & N & N & Y \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Comparison between MedChain and related solutions. First is the data movement issue. If a patient migrates to a new city, access to his/her data in the previous hospital will always require inter-organizational data sharing, which results in additional overhead in diagnosis. A possible improvement is to implement data transfer between two healthcare organizations. In practice, however, medical records are in custody at healthcare providers. Thus, data movement requires design at both the technical and the regulatory level. Another limitation of this research is that the access of data requires patient's manually approval, which increases the operation overhead of the patient and the access latency of the requester. The limitation could become a bottleneck in an emergent healthcare provision. Thus, in the future, we plan to work on automatic data sharing such that an authorized device, such as a smart phone, can initiate a data sharing session when it receives the request from a doctor. It could be achieved by adding the related rules and conditions configured by users. Moreover, currently, MedChain still needs healthcare providers to manually upload the information of data streams to the blockchain service and the directory, which is not efficient.