## 4 Experiment
### Experiment Program  
Table 8 shows the functionality supported by our blockchain system and the three data-storage methods of ethereum as found from Experiment 1. As shown in Table 8, ethereum cannot be applied to the application scenario of data-transaction access control. We can also see that only the log-event storage method of ethereum can support massive-data transfers that are greater than 1 MB. Therefore, in summary, the blockchain system proposed in this paper has advantages in terms of privacy, access control, and large data-file transactions. In Table 9 we show the results from Experiment 2 for storage-space consumption required by the different blockchain platforms for varying sizes of transaction data. In ethereum, the maximum storage space that the block storage method can support is 80 B, and the fixed fee for each transaction is 21,000 gas. The extra cost for each stored byte is 68 gas, so the total cost of storing 80 B data is 26,440 gas. The contract variable storage method can store up to 32 KB. The transaction fixed cost is the same as before, and variables for store operations cost 20,000 gas. Each 1 KB of data costs 68 gas, so this makes a total of 43,176 gas. The third storage method uses smart-contract log events to store data. This can satisfy all transaction-data sizes for Experiment 2. Each log costs 375 gas, each 1 KB of data stored in the log costs 8 gas. The fourth type, the blockchain system introduced in this paper, only needs to record the 32 B hash value calculated through the IPFS protocol on the file, multiply it by 68 gas, add 21,000 gas, and the calculated gas value is 23,176 gas. It can be clearly seen from Figure 17 that the data capacity supported by ethereum's Methods 1 and 2 is limited and cannot support massive amounts. Method 3 can support massive-data-sharing transactions, but as the amount of data increases, the cost of required gas linearly increases. \begin{table}
\begin{tabular}{c c c c} \hline  & **Feature Support** & **Access Control** & **Access Control** \\ \hline \multirow{3}{*}{Ethereum platform} & Block storage & no & no \\  & Contract variable & no & no \\  & Log event storage & no & yes \\  & & yes & yes \\ \hline \end{tabular}
\end{table} 
Table 8: Access-control and data-storage function support records. \begin{table}
\begin{tabular}{c c c c c c c} \hline  & **Transaction Data Size** & **80 B** & **32 KB** & **600 KB** & **1.2 MB** & **5.4 MB** \\ \hline \multirow{3}{*}{Ethereum platform} & Block storage & 80 B & - & - & - & - \\  & Contract variable & 80 B & 32 KB & - & - & - \\  & Log event storage & 80 B & 32 KB & 600 KB & 1.2 MB & 5.4 MB \\ Multi-layer blockchain model & & 32 B & 32 B & 32 B & 32 B & 32 B \\ \hline \end{tabular}
\end{table} 
Table 9: Effect of transaction data size on storage consumption. The multicenter blockchain model proposed in this paper adopted the storage method under the file-data chain. Only the hash value of the relevant file data is stored in the chain, which saves storage consumption from the blockchain. At the same time, this blockchain platform is different from public chains such as bitcoin and ethereum. It does not need to spend extra money in the transaction process. Therefore, in summary, the platform compares favorably with existing blockchain technologies such as bitcoin and ethereum. Experiment 3 mainly analyzed the TPS parameters. By comparing the \(TPS\) parameters of bitcoin, ethereum, and our platform, the performance of the consensus algorithm introduced in this chapter was compared. According to Formula 1, we took time interval t as 10, 20, 40, 80, 160, and 320 s, respectively, and tested each time interval tenfold. The data of each test are shown in Table 10.  
According to the recorded data condition in Table 10, each interval separately averaging 10 data, we concluded that each interval of the average number of trading, through six obtained \(TPS\) value formulas, based on the conclusion from six \(TPS\) average blockchain systems in the \(TPS\) experiment was about 1500 or so.