# Generic Patient-Centered Blockchain-Based EHR Management System
## 3 Framework Components  
In this study, as shown in Figure 2, we established a permissioned infrastructure in an Ethereum Blockchain framework that allows complete control of records by patients while ensuring privacy, durability, and security. This is carried out by maintaining health information primarily on the blockchain as hashes, whereas the original bulk quantities of data are stored off-chain in IPFS to guarantee effectiveness and scalability.  
The smart contract chain code protocol in this paper is termed a Patient-Centric Healthcare Data Management Access Control-Smart Contract, in which this SC is used to write the role-based access control chain code for recognized stakeholders involved and does not employ any incentive mining beyond ensuring that every party has equal access to the system. The role-based unique ID is initiated after the registration of stakeholders. Following this process, public and private key pairs are provided to each stakeholder for the storage and transfer of health information. In this architecture, a patient's health record is created by doctors. Subsequently, the patient would commit the encrypted health  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Ref** & **Implemented Problems** & **Problem to Be Solved** \\ \hline
[7] & Data Integrity and Interoperability & Privacy and scalability \\
[10] & Sharing if Data and Integrity of Data & Privacy and scalability \\
[11] & Public data access and Integrity of data & Interoperability and authentication \\
[13] & Interoperability & Secure, Privacy, and Scalability \\
[15] & Privacy and Security & Scalability and Interoperability \\
[16] & Scalability and interoperability & Privacy \\
[17] & Security & Scalability and Privacy \\
[18] & Security and Privacy & Scalability \\ \hline \hline \end{tabular}
\end{table}
Table 2: Several solutions of the existing techniques EHR systems currently lack adequate interoperability to provide private, effective, and secure access control.  
Figure 2: Framework of the proposed system.  
record to be stored in IPFS indelibly while the record hash from IPFS is conserved via the Ethereum blockchain.  
In the event that the doctors need to update the patient's health record, one can allow or block the process by granting or revoking access, respectively. The temporary view, or patient-centric view, of the health record, is constructed from IPFS. In this view, the doctor is allowed to update the documentation before the patient commits to the update using their key pairs to save the updated files in IPFS. In this way, this framework would ensure the interoperability of the mechanism.  
Additionally, patients have the right to grant access to share the records with only the relevant stakeholders in a patient-centric view of the record from the IPFS system. A doctor's session also would expire before the hash value is committed to the ledger so that non-concerned personnel would have gained access to a record without the patient's permission, hence, safeguarding the data privacy in the system. At the back end, smart contracts are generated for several healthcare procedures.  
Hence, role-based access control employed in this framework protects the privacy of the patient. Moreover, our proposed system also has improved scalability and interoperability features as compared to the current system.