# Process Automation and Blockchain in Intelligence and Investigation Units: An Approach
## 3 Literature Review: Background and Related Work
### Blockchain Technology
With the growing interest in blockchain technologies, the application scope is extensive and can be divided into public, consortium, and private blockchains types. Table 2 presents a general comparison on types of blockchain [46; 47; 50; 52; 53; 54]. According to [PERSON] [37], with the use of blockchain technology there is the possibility of implementing processes aimed at recording data and assets, as well as storing and exchanging \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Public** & **Private** & **Consortium** \\ \hline \multirow{3}{*}{Definition} & Participation in transactions or consensus & They are used in a single organization, & \multirow{3}{*}{\begin{tabular}{c} Operators under the leadership of a group of organizations. Only chosen participants can join the network with restricted participation} \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \cline{3-3}  & & & \\ \hline \multirow{3}{*}{Access} & Read: Open & Read: Open/permissioned & \multirow{3}{*}{\begin{tabular}{c} Read: Open/permissioned \\ Write: Permissioned \\ Consensus Permissioned \\ \end{tabular} } & \multirow{3}{*}{\begin{tabular}{c} Peer: Permissioned \\ Consensus Permissioned \\ \end{tabular} } \\ \cline{3-3}  & & & & \\ \cline{3-3}  & & & \\ \hline \multirow{3}{*}{Security} & Proof-of-work [36], proof-of-stake [55], & \multirow{3}{*}{\
\begin{tabular}{c} Practical Byzantine Fault-Gleaned [56], \\ Refu [57], legal contracts, proof of \\ authority \\ \end{tabular} } & \multirow{3}{*}{
\begin{tabular}{c} Practical Byzantine Fault-tolerance [56], \\ refu [57], legal contracts, \\ proof of authority \\ \end{tabular} } \\ \cline{3-3}  & & & & \\ \hline Privacy & Medium & High & High \\ \hline Environment & Untrusted & Trusted & Trusted \\ \hline Speed & Slow & Fast & Fast \\ \hline Cost & High & Medium & Low \\ \hline Architecture & Decentralized & Partially decentralized & Partially decentralized or centralized \\ \hline Transaction rate & Slower & Faster & Fastest \\ \hline Membership & Anonymous/pseudonymous & Known identity & Known identity \\ \hline Typical platforms & Bitcoin [36], Ethereum [44], Litecoin [58] & HyperLedger [49; 59], R3 Corda [60] & HyperLedger [49; 59], R3 Corda [60] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Blockchain types (public, private, and consortium). Figure 4: The chain data structure of blockchain. information on both physical and intangible assets (e.g., ideas, health data, voting results). Enabling the monitoring of the ledger by the participating organizations, creation, evolution, and monitoring of the immutable history of transactions is jointly conducted. Different approaches were proposed in academic researches that were related to blockchain application in the context of data and digital assets management, storage, and/or sharing,  
[PERSON] et al. [61] presented general discussions on the use of the blockchain technology, aiming to provide a solution for dynamic asset sharing among members of a consortium. The solution was focused on the creation of a logical and centralized asset management system composed of participants who followed a previously defined policy. In order to provide authenticity and data quality (including from purchasing customers), and to provide a stable business platform for asset owners, a framework aimed at data sharing and forwarding digital assets based on blockchain technology has been proposed [62]. In this scenario, the following were combined: decentralized storage, Ethereum blockchain, encryption, interplanetary file system (IPFS) benefits, smart contract, and incentive mechanism. Regarding the healthcare domain, a novel drug supply chain management system implemented in Hyperledger Fabric has been proposed [45]. The records of transactions where performed based on a blockchain to handle drug supply chain data with the objective of creating a smart healthcare ecosystem that enabled access to patient health data and medicines through smart contracts.