# Development and Pilot-Test of Blockchain-Based MyHealthData Platform
## 4 Discussion  
We developed the MyHealthData service, a blockchain-based mobile platform that can exchange health information with proven integrity on a dynamic consent system with self-determination of the data subject. A total of 1228 people joined the service, and inquiring about medical or health checkup records was the most frequently used function. Users were able to download their own MyData that was stored in medical institutions. MyData is a system in which the data subject proactively utilizes their personal information scattered among various institutions as a system for exercising their rights of self-determination [5]. It is accomplished by downloading and using data owned by the person or by providing consent for third-party use [27]. It is also possible to deposit personal information where it is needed and receive compensation for services based on that information. Since data is used as an individual's right to self-determination, there is no need to amend the law, and it is a system that can be implemented immediately because information loss due to non-identification measures can be avoided [28; 29]. The United States introduced the Blue Button concept in 2010, which aims to enable direct consumer access to personal medical information. If the individual consens, a single electronic file containing available health data can be downloaded [30]. Blue Button was introduced where healthcare data is needed, such as an HIS. The Office of the National Coordinator for Health IT (ONC) is helping to develop standards and technologies so that the Blue Button service can be easily extended to various fields such as pharmaceutical companies, insurance companies, and research institutes, as well as the medical field [30]. The European Union has promoted a Re-Health project that aims to design an integrated Electronic-PHR (E-PHR) platform that aims to store health data and related information in one electronic document [31]. Taiwan's National Health Insurance (NHI) has issued health smart cards to all citizens since 2001. The Integrated Circuit (IC) chip in the card stores the patient's last six medical records, and allows the medical records to be queried through medical institutions [32]. However, the current MyData service is limited because it cannot prove that the data has not been forged or altered [33]. In South Korea, all medical institutions use various kinds of HISs and have developed and utilized different types of PHRs. In addition, each healthcare service provider, such as \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Questions** & **Mean \({}^{*}\)** & **SD** \\ \hline Perceived ease of use & Are the results of data use being serviced in an & 3.85 & 0.87 \\ Perceived ease of use & easy-to-understand manner? & 3.85 & 0.86 \\  & Is the consent to provide selective personal information being & 3.85 & 0.86 \\  & serviced in an easy-to-see manner? & 3.95 & 0.86 \\ Perceived usefulness & Does the service provide useful information/functions to users? & 3.90 & 0.92 \\  & Are you willing to continue using the service? & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Perceived usefulness and perceived ease of use surveys. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Service Types** & **Mean \({}^{*}\)** & **SD** \\ \hline Inquire medical and health checkup records & 3.91 & 0.86 \\ Health coaching & 3.82 & 0.88 \\ Claim private insurance & 3.76 & 0.99 \\ Check conditions for clinical trial & 3.85 & 0.92 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Satisfaction survey. a clinic or hospital, has long been thought to own medical data. Uniquely, South Korea has a medical system based on the National Health Insurance Service (NHIS), which has been collecting billing data and general health checkup results from all healthcare service providers. However, health records are fragmented among the health care institutions that patients visit, as the EHR systems used by each institution are different and most are not interoperable [34].