# Blockchain Integration in the Era of Industrial Metaverse
## 2 Historical Evolution of the Blockchain
### Blockchain 4.0  
So far, the previous blockchain generations have not yet adequately achieved the industrial goals; thus, the needs of industries relevant to the technological pillars and advancements of Industry 4.0 are still open for further development [17]. For example, to achieve the required level of industrial automation, a new generation of blockchain is required. The key requirements of Industry 4.0 are the integration of cybersecurity and innovative technologies such as supply chain management [18], the Internet of Things (IoT), and AI. Therefore, the introduction of a new blockchain era, under the name \"Blockchain 4.0,\" following the technological advances to serve businesses with enhanced privacy, security, transparency, and data integrity is required [19]. As a result, InterValue has been utilized for the creation of a Blockchain 4.0 platform. The main target of InterValue with Blockchain 4.0 is to create an improved version of a Directed Acyclic Graph (DAG) with improved scalability, usability, and reliability [20; 21].  
Blockchain 4.0 applications and their application in various industrial sectors have been discussed in several publications due to the improvements versus its previous generations in terms of scalability, interoperability, and transaction rate [22]. Growing technologies such as blockchain and software-defined networking (SDN) can be used to build secure systems and guarantee secure network connectivity [23]. As a result, in the near future, improvements regarding aspects such as scalability, security, and transparency of the blockchain network are to be expected for industrial implementations.  
Based on the discussion in the previous paragraphs regarding the discrete evolutions of blockchain, the following comparative table (Table 2) has been compiled in order to explicitly highlight the key implications of the blockchain evolutions, taking into consideration various parameters, among them the key technology used, the consensus mechanism, the data rate for the completion of digital transactions, etc.  
\begin{table}
\begin{tabular}{p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt} p{56.9 pt}} \hline \hline
**Parameter** & **Blockchain 1.0** & **Blockchain 2.0** & **Blockchain 3.0** & **Blockchain 4.0** \\ \hline Underlying technology & Distributed leder technology (DLT) & Smart contracts & Decentralized Applications (DApps) & Blockchain with AI \\ \hline Consensus mechanism & Proof of Work & Delegated Proof of Work & Proof of Stake, Proof of Authority & Proof of Integrity \\ \hline Validation & By miners & Through smart contracts and miners & In-built verification mechanism via DApps & Automated verification via sharing \\ \hline Scalability & Non-scalable & Poorly scalable & Scalable & Highly scalable \\ \hline Intercommunication & Not possible & Not possible & Possible & Possible \\ \hline Data rate & 7 TBS & 15 TBS & 1000 s of TBS & 10\({}^{6}\) TBS \\ \hline Cost & Expensive & Cheaper & More cheaper & Cost effective \\ \hline Energy consumption & Highest & Moderate & Energy efficient & Highly efficient \\ \hline Example & Bitcoin & Ethereum & IOTA, Cardano, Anion & SEELE, Unibright \\ \hline Application & Financial sector & Non-financial sector & Business platforms & Industry 4.0 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Comparative analysis of blockchain evolutions.