# A Blockchain-Based Secure Inter-Hospital EMR Sharing System
## 5 Conclusions  
With the growth of medical technology, medical information is becoming increasingly important in terms of patient identity background, medical payment records, and medical history. This can be the most private information about a person, but due to some issues, such as operation errors within the network or hacking attacks by a malicious person, there have formerly been major leaks of sensitive personal information. In any case, this has become an issue worth studying to ensure the privacy of patients and protect these medical materials.  
On the other hand, under the current medical system, the patient's medical record cannot be searched across different hospitals. When the patient visits another hospital for treatment, repeated examinations will occur, resulting in a waste of medical resources. Therefore, inter-hospital medical record access is also a very important goal. This study draws on blockchain technology to propose a secure inter-hospital EMR sharing system. Assuming that the hospitals and the patients are in the same medical alliance, the blockchain center will issue identity verification keys to these members. After this, the alliance members can conduct legal communication and data exchange in the future. Thus, the medical records of the patients will be accessible. This can prevent the waste of medical resources and achieve higher medical quality and efficiency. The proposed scheme meets a variety of security requirements, and the BAN logic proof model is applied to assess the correctness of the proposed scheme. The proposed scheme performs quite well in terms of computational and communication costs. In the future, the prospect of using blockchain-based technologies the medical field is becoming increasingly likely. While protecting personal privacy and sharing medical resources, how could the blockchain transaction become efficient? This is another research direction by which to compare blockchain-based platforms in a performance evaluation.  
\begin{table}
\begin{tabular}{l c c c} \hline \hline
**Functionality** & **Scheme** & **[PERSON] et al. (2019) [43]** & **[PERSON] et al. (2019) [44]** & **Our Scheme** \\ \hline Blockchain & Yes & Yes & Yes \\ Architecture & & & \\ Mutual & Yes & Yes & Yes \\ Authentication & Yes & Yes & Yes \\ Data Integrity & Yes & Yes & Yes \\ User & Yes & Yes & Yes \\ Untraceability & & & \\ Resistance to & Yes & Yes & Yes \\ Replay Attack & & & \\ Forward and & & & \\ Backward & Yes & Yes & Yes \\ Secrecy & & & \\ Nonrepudiation & No & Yes & Yes \\ BAN Logic & No & No & Yes \\ Proof & & & \\ Inter-Hospital & & No & No & Yes \\ Authentication & & & \\ \hline \hline \end{tabular}
\end{table}
Table 4: Functionality comparison of previous schemes and the proposed scheme.  
**Author Contributions:** The authors' contributions are summarized below. [PERSON] and [PERSON] made substantial contributions to the conception and design and were involved in drafting the manuscript. [PERSON] and [PERSON] acquired data and analysis and conducted the interpretation of the data. The critically important intellectual contents of this manuscript were revised by [PERSON] All authors read and approved the final manuscript.  
**Funding:** This study is supported by the Ministry of Science and Technology (MOST), Taiwan, Republic of China, under the grant MOST 108-2221-E-324-013.  
**Conflicts of Interest:** The authors declare no conflict of interest.