# Exploiting Blockchain Technology for Enhancing Digital Twins' Security and Transparency
## 4 Experimental Results
### Performance Benchmarks
#### 4.3.2 Benchmarks on Throughput
In this scenario, the Clique algorithm also reaffirmed its position as the protocol with the lowest latency, although it demonstrated a lower transaction approval rate compared to the others, due to the probabilistic nature of its consensus mechanism. Instead, the IBFT 2.0 and the QBFT algorithms exhibited similar behaviors in terms of throughput, as indicated by the corresponding measurement plots. However, a steady increase in latency was observed for IBFT 2.0 as the network size grew, reaching its peak at the maximum size of the network. In fact, the latency recorded by the IBFT 2.0 algorithm consistently remained lower than that of the QBFT, establishing a lower bound for its latency in comparison. The narrow latency gap between these two consensus protocols necessitates further analysis in the subsequent sections to determine the most suitable protocol for the specific security requirements of our system's environment. To clarify the obtained benchmark results and designate a suitable consensus algorithm for our system's purposes, we conducted an additional test on these two protocols based on varying transaction send rate configurations. The test highlighted the measurements obtained in a simulated utilization of the real system described in Section 5 through its canonical use. Moreover, we tested the capabilities of the network to serve in both sending and receiving hash modalities. The objective of these tests was to evaluate the system's performance under high transaction loads. Specifically, assuming a transaction rate of 60 transactions per second from the different instances of the sender devices, the analysis determined whether the system could support up to \(N\) occurrences in the real environment. Analyzing the performance of the QBFT and the IBFT 2.0 algorithms, as presented in Figure 8, it was observed that both algorithms exhibited similar latency and throughput characteristics. However, QBFT demonstrated greater resilience to increasing transactions per second compared to IBFT 2.0. These benchmarks illustrated the number of transactions successfully validated (represented by solid lines) in relation to the number of transactions sent per second (represented by dashed lines). Through these tests, the architecture of our blockchain network could be effectively defined. Summarizing the results, the series of tests conducted in this paragraph on the underlying blockchain framework and the associated consensus protocols led to the selection of the QBFT algorithm as the underlying algorithm for our solution. Although the Clique protocol initially appeared promising for the offered transaction speed, it demonstrated instability early in the scaling and stress tests. In contrast, both QBFT and IBFT 2.0 maintained comparable performance across the benchmark suite. However, under conditions of increased network load, subtle but significant performance distinctions emerged between the two protocols, ultimately favoring QBFT. Additionally, the network architecture proposed was configured to operate with six nodes. This specific number of validators was chosen based on observed optimal performance outcomes of the QBFT protocol, guaranteeing enhanced fault tolerance and network resilience. The provided benchmarking results demonstrated the suitability of the QBFT consensus protocol compared with the proposed requirements for the real-time digital twin updates, maintaining a constant transaction throughput even during peak loads while minimizing the overall latency. These metrics directly correlated with the system's objective to provide a secure yet responsive digital twin framework, ensuring its scalability for high-demand industrial scenarios like supply-chain monitoring and other IoT-enabled solutions. It should be noted that other DLT models with different degrees of security and performance could be evaluated for implementing the proposed approach.