## 4 SSHies: An Era of Research
### Blockchain and Smart Contracts-Based Techniques in HIE Systems: A Background
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Ref.** & **Year** & **Method** & **Data Set** & **Performance** \\ \hline
[75] & 2021 & Patient-centric platform & Not available & High integrity and resiliency \\ \hline
[76] & 2023 & \begin{tabular}{c} modules blockchain \\ architecture \\ \end{tabular} & \
\begin{tabular}{c} 3 millions \\ transactions \\ \end{tabular} &
\begin{tabular}{c} Proc. time = 1.42 s; \\ stability with \\ high throughput \\ \end{tabular} \\ \hline
[77] & 2022 & CEDA + DERY & NA & Correctness and \\  & & & & high security \\ \hline
[78] & 2022 & \begin{tabular}{c} Medical diagnosis \\ analysis \\ \end{tabular} & \
\begin{tabular}{c} Amazon M-Turk, \\ Qual tricks M-Turk \\ \end{tabular} &
\begin{tabular}{c} High security \\ and applicability \\ \end{tabular} \\ \hline
[105] & 2022 & \begin{tabular}{c} Coupling blockchain \\ and IPPS \\ \end{tabular} & \
\begin{tabular}{c} [[https://docs.ipfs.tech/](https://docs.ipfs.tech/)]([https://docs.ipfs.tech/](https://docs.ipfs.tech/)) \\ concepts/dht/ \\ (accessed on 30 January \\ 2024) \\ \end{tabular} &
\begin{tabular}{c} Compression ratio \\ on-chain, \\ off-chain = 0.0085, \\ rate = 99.1 \\ \end{tabular} \\ \hline
[79] & 2023 & \
\begin{tabular}{c} Encryption technique, \\ Blockchain, Access \\ control \\ \end{tabular} & NA &
\begin{tabular}{c} Proc. time = 1.5 s, \\ high efficiency \\ and privacy \\ \end{tabular} \\ \hline
[80] & 2022 & \begin{tabular}{c} Three-layer blockchain \\ architecture \\ \end{tabular} & \
\begin{tabular}{c} Beoutbreakprepared \\ \end{tabular} &
\begin{tabular}{c} Latency = 1507 ms, \\ IBT Vs 21257 POW, \\ throughput = 62 T/s \\ \end{tabular} \\ \hline
[81] & 2022 & \begin{tabular}{c} SABE-based \\ blockchain \\ \end{tabular} & \
\begin{tabular}{c} Medical data set of \\ a group of patients \\ \end{tabular} &
\begin{tabular}{c} Setup time \textless{} 10 ms, \\ key generation \\ time \textless{} 10 ms, \\ encryption time \\ \textless{} 70 ms \\ \end{tabular} \\ \hline
[82] & 2017 & \
\begin{tabular}{c} OmniPHR \\ \end{tabular} & NA &
\begin{tabular}{c} High latency \\ and scalability \\ \end{tabular} \\ \hline
[62] & 2019 & \begin{tabular}{c} OmniPHR using \\ large set of \\ concurrent sessions \\ \end{tabular} & \
\begin{tabular}{c} 2 hospital databases, \\ Virtuoso database \\ \end{tabular} &
\begin{tabular}{c} Response time \\ \textless{} 500 ms, \\ availability = 98\% \\ \end{tabular} \\ \hline
[45] & 2019 & \
\begin{tabular}{c} Blockchain and \\ mobile application \\ \end{tabular} & NA &
\begin{tabular}{c} High privacy \\ and scalability \\ \end{tabular} \\ \hline
[83] & 2018 & \
\begin{tabular}{c} IOTA protocol, \\ MAM \\ \end{tabular} & NA &
\begin{tabular}{c} Integrity using \\ MAM, \\ latency \textless{} 1 ms \\ \end{tabular} \\ \hline
[84] & 2018 & FHIRChain & HapiFHR &
\begin{tabular}{c} High scalability, \\ modularity, and \\ trust \\ \end{tabular} \\ \hline
[85] & 2022 & \
\begin{tabular}{c} Consensus algorithms, \\ Blockchain \\ \end{tabular} & NA &
\begin{tabular}{c} High security \\ and privacy \\ \end{tabular} \\ \hline
[46] & 2021 & \begin{tabular}{c} Blockchain, access \\ control, cryptography \\ \end{tabular} & \
\begin{tabular}{c} [[https://github.com/](https://github.com/)]([https://github.com/](https://github.com/)) \\ asmaadnane/ \\ Blockchain-healthcare \\ (accessed on 30 January \\ 2024) \\ \end{tabular} &
\begin{tabular}{c} High confidentiality, \\ privacy, access \\ control, and \\ scalability \\ \end{tabular} \\ \hline
[86] & 2023 & \
\begin{tabular}{c} Tendermint, BigchainDB, \\ MongoDB, encryption \\ algorithms \\ \end{tabular} & NA &
\begin{tabular}{c} High privacy \\ and security, \\ AES-256 algo. \\ \end{tabular} \\ \hline
[87] & 2016 & \
\begin{tabular}{c} Merkle tree-based \\ scheme, hashing, \\ Miner Election \\ algorithm \\ \end{tabular} & HapiFHR &
\begin{tabular}{c} High efficiency \\ and security \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Integration of blockchain and smart contracts into HIE systems: a summary.