## 4 Blockchain Adoption in Healthcare
### Proposed Solution Taxonomy  
Based on the review conducted, several challenges, issues, and loopholes have been identified in the existing HMS in Section 4. To resolve these challenges, BC can be an efficient solution. Healthcare data exchange is crucial for creating an efficient healthcare system and delivering high-quality healthcare services. Healthcare information is a valuable and private asset that patients must own and control. The present study proposes a solution taxonomy for a global healthcare management system in order to govern, own, securely access, and exchange information in accordance with patient authentication without compromising patient privacy. The proposed solution can be implemented in order to develop a full-stack blockchain-based framework for decentralized identity and robust data management for medical records in a global healthcare management system. The proposed solution taxonomy is divided into four components:  
* **Block Creation:** The first time the information is entered, a new block will be created;
* **Patient Identity Management:** Once the block is created, a unique key for the patient will be generated that will act as a primary key in the distributed database. This identity or key will only be used for accessing patient records globally;
* **Data Management and Interoperability:** The patient health record information, such as disease symptoms, prescriptions, X-ray reports, lab reports, etc., will be inserted into the database, and the new block with the hashed key will be appended to the blockchain. Once a block is created, it becomes immutable that cannot be deleted. Any node could share the interoperable data with due permissions; \begin{table}
\begin{tabular}{p{142.3 pt} p{142.3 pt}} \hline \hline
**Blockchain-Based HMS** & **Summarized Application Features** \\ \hline MedRec [75] & MedRec, product of MIT Media Lab and Beth Israel Deaconess Medical Center based on Ethereum. It targeted giving patients control over their information to determine who can get to them through fine-grained admittance consents based on blockchain. \\ \hline Medicalchain [81] & Medicalchain has been developed utilizing a double blockchain structure. The first blockchain controls admittance to health records and was constructed utilizing Hyperledger Fabric. The second blockchain is on Ethereum, using the ERC20 token for administrators of the platform. \\ \hline Ancile [82] & A blockchain-based structure developed on Ethereum blockchain using smart contracts for efficient and secure access control, non-repudiation of data, and utilized enhanced cryptographic procedures for additional security. \\ \hline DPS [83] & Data preservation system based on Ethereum provided dependable data storage assuring the evidence of information while safeguarding security for critical health. \\ \hline MedBlock [79] & MedBlock, a distributed ledger, two-layer architecture with a block structure based on Merkle-Tree, permitted effective EMR access and EMR recovery [79]. The hybrid consensus system accomplished the agreement of EMRs without huge energy utilization and organization clog. \\ \hline MedShare [80] & MedShare, a framework that addresses the issue of enormous health data sharing among big data seekers. MedShare provided information provenance, examination, and control for shared health information in a cloud. \\ \hline FHIRChain [78] & A system intended to meet ONC (Office of the National Coordinator for Health Information Technology) prerequisites by epitomizing the HL7 Fast Healthcare Interoperability Resources (FHIR) standard for shared medical information. A decentralized application has been developed based on computerized medical identity for distant tumor care. \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Summary of popular blockchain-based HMS. * **Consensus and Security:** If an existing record is to be searched or shared, it must be validated using a patient-hashed key and a joint consensus of the doctor/hospital and patient.