# Trustworthy Transaction Spreading Using Node Reliability Estimation in IoT Blockchain Networks
## 5 Experiments
### Performance Evaluations: Valid Transaction Sharing and Valid Block Sharing  
To demonstrate the effectiveness of the proposed method, arbitrarily malicious nodes perform an eclipse attack or create a fake transaction. An eclipse attack refers to the act of a malicious node manipulating the routing table to isolate neighboring nodes. The attacked neighboring node cannot recognize the network situation, and a malicious node can fill in fake routing information into the routing table of the neighboring node [47]. The proposed trustworthy transaction spreading method selects a highly reliable border node and traverses the path by bypassing the lower reliable area in the transaction spreading process. The proposed method then allows the network to share valid transactions among trusted nodes. Random nodes were selected as malicious nodes, and neighbor nodes connected by one hop were set as attack targets. After 100 transaction traverses with arbitrary origins and destination nodes, we calculated the percentage of nodes sharing the transaction. For comparison, the results of the random spreading and gossip techniques are shown (see Figure 7). The proposed trustworthy transaction spreading method significantly outperforms other techniques in terms of the transaction sharing rate. In addition, it can be confirmed that the performance is relatively robust, even with an increase in the number of malicious nodes. Figure 8 shows the duplicated transaction rates. We define the duplicated transaction rate as 100% when a single transaction of each traverse is stored in all the nodes. To calculate the duplicated transaction rate, the total number of transactions stored in all the nodes was counted and subsequently divided by the number of network nodes. The proposed trustworthy transaction spreading method significantly outperforms other techniques in terms of duplicated transaction rates. It guarantees transaction verification capability through sufficient duplicate transactions. The random spreading method resulted in excessive duplications. It is a heavy burden to maintain transactions for small-scale IoT nodes. The gossip method had a minute number of duplications. Gossip has the advantage of rapidly reaching the destination node. However, insufficient duplications are disadvantageous in terms of blockchain stability. It is difficult to find a special correlation between the increase in malicious nodes and duplicated transaction rates for all three methods (trustworthy spreading, random spreading, and gossip). The energy usage is proportional to the number of transactions required to validate the blocks or transactions. We assume WiFi connectivity between nodes. A report from [PERSON] et al. [48] illustrated the energy consumption per WiFi message transmission. We assume that the transmission power of the network node is 10 dBm with 10 mW needed to publish a single transaction (we fix the transmission speed to 100 kbps, which is sufficient for sensing or actuating IoT nodes). The duplication transaction rate is the direct measure of the number of transaction transmissions between two devices. The average duplicate transaction rates are 93.1%, 236.5, and 28.7% for trustworthy transaction spreading, random spreading, and gossip, respectively. We can estimate the energy consumption for each device as 931 mW, 2365 mW, and 287 mW for 100 transactions traversed in the experiments. In Figure 9, we compare the valid block sharing rate when a malicious node intervenes in the block validation process. Malicious nodes attempt to propagate fake blocks to the  
Figure 8: Duplicated transaction rate. (**a**) Single malicious node; (**b**) Double malicious node; (**c**) Triple malicious nodes. Figure 7: Transaction sharing rate. (**a**) Single malicious node; (**b**) Double malicious node; (**c**) Triple malicious nodes. network in PBFT block validation consensus.