## 5 Results and Evaluations  
All of the results obtained below were generated using the system specification shown in Table 1.  
Figure 8: SAML code for information access.  
Figure 9: Complete implementation diagram.  
The use of the blockchain in the communication process protects the medical data by encrypting it using asymmetric cryptography. It also improves the efficiency in terms of the total cost of the system for storage and document access. The comparison of this study with other EHR systems shows that the document access and retrieval time is faster in the proposed approach compared to that in the other systems. Table 2 summarizes the comparison between the system under study and other existing systems. The data in Table 2 clearly indicate the superiority of the system under study with respect to the existing alternatives ([50,51,60,61]). The alternative approaches are either centralized or semi-centralized. This is in contrast to the system under study, which is based on a decentralized network, thus making it durable and coherent in terms of availability and access.  
The storage type used by [51] is a mutable peer-to-peer storage network with manual entry by the health personal, and [60] uses picture archiving and communication systems (PACS). As a result of their respective approaches, both of these systems are vulnerable to data attacks by hackers, and to anomalies created due to the duplication of data. The proposed system is superior due to its use of an immutable blockchain technology and hashes to store data, which removes the probability of data duplication. The proposed system provides users full command of their information with greater security, clarity, and integrity. Due to the use of a blockchain, the proposed system's transactions are not prone to deletion and information can be easily recovered in the case of a node failure. Encryption and decryption on all the comparative systems are performed manually, which can cause data issues. In contrast, the proposed system utilizes the advantages of the built-in features of the blockchain technology for encryption and decryption. Protection of documents after decryption is also an issue, which is resolved in this system with the use of digital signatures.  
The proposed system also provides a great deal of resilience against cyber-attacks, thus improving the overall security of the system. This resilience is not provided by any of the comparative approaches. The proposed system is based on encryption and each transaction is encrypted prior to transfer. Due to the use of asymmetric encryption and immutable storage, the proposed system is secure and transaction alteration is almost impossible due to the presence of the distributed ledger, which protects it from alterations. Due to the fault tolerance of RAFT, the consensus algorithm used in this study, the system is robust and reduces the downtime of the network.  
\begin{table}
\begin{tabular}{c c} \hline
**Specification** & **Value** \\ \hline CPU & Dell server (intel 3.4 quad-core i7) \\ Memory & 32 GB \\ Network Bandwidth & 4 Mb CIR \\ Concurrent blockchain nodes & 20 \\ \hline \end{tabular}
\end{table}
Table 1: Specification of the environment.  
\begin{table}
\begin{tabular}{c c c c c c} \hline
**Schemes** & [60] & [50] & [61] & [51] & **Proposed System** \\ \hline Source Data & Yes & Yes & Yes & Yes & Yes \\ Data Storage Type & PACS & Cloud Server & Dedicated & Mutable P2P & Immutable Storage \\ Tamper Proof & No & Yes & Yes & Yes & Yes \\ Encryption Type & Not Mentioned & Not Mentioned & Symmetric & Asymmetric & Asymmetric \\ Database Sharing & PACS & Blockchain & Blockchain & Blockchain & Blockchain \\ Smart Contract & No & Yes & No & No & Yes \\ Attack Resilience & No & No & No & Yes \\ Database Type & Centralized & Centralized & Centralized & Semi-Centralized & De-Centralized \\ \hline \end{tabular}
\end{table}
Table 2: Comparison between existing frameworks and the proposed system.