## 3 Multilayer Blockchain Model Supporting Massive Data Hierarchical Authorization Transactions
### Privacy Access Control Design  
Taking a transaction between Organizations A and B as an example, Organization A initiates a data transaction to organization B. Organization B obtains the data content through the transaction. However, the organizations involved in the transaction want this to be done in private and do not wish other users of the platform to view them or the transaction information, or obtain the data content. Therefore, the transaction cannot go through the process of reaching consensus across the entire network. Therefore, Organizations A and B can only reach a consensus between themselves through the channel mechanism. This is done by establishing a consensus service node independent of the organizations. Adding Organizations A and B, and the consensus service nodes to the channel, consensus ordering is conducted by the consensus service node for the transactional data between Organizations A and B. The data information for the transaction is stored only in the books of Organizations A and B. Through this method, external organizations cannot see the specific transaction  
Figure 6: Identity-authentication certificates (ICert) mechanism flowchart.  
Figure 7: Transaction-authentication certificate (TCert) mechanism flowchart.  
information between Organizations A and B, and the access control function is realized. The schematic diagram of the channel permission control mechanism is shown in Figure 8.  
The thick black lines shown in Figure 8 are the connections of the channel pipelines. There are two transactions: Transaction 1 contains node Peer1 at ORG1 and peer1 at ORG2. Transaction 2 contains node Peer2 at ORG1, Peer2 at ORG2, and Peer1 at ORG3. These two transactions are isolated from each other by the system. In the blockchain network, the same node of the same body can participate in different channel pipelines, and the same channel can be joined by different nodes of different organizations. These transactions can only be seen by nodes joining the current channel pipeline, and other nodes cannot see the relevant information of the transaction. Nodes of the same channel generate the same accounting information, and nodes of different channels have different accounting information. The channel mechanism relies on the consensus service algorithm to realize the privacy access control of the platform. By dividing the multicenter blockchain model into multiple logical channels, nodes participating in different transactions are included in different channels, which is well-adapted to data-sharing transactions.  
The implementation of the channel mechanism also depends on support provided by the message queue. The topic queue and the broadcast mechanism of the message queue can handle the channel function well, and nodes of the same channel send the same accounting information to the consensus service node through the message queue. The corresponding relationship between multichannel and ledger is shown in Figure 9.  
As shown in Figure 9, there is a one-to-one correspondence between channel and ledger. In the figure, the Peer1 node joins Channel1, Channel2, and Channel3, so the books of the three channels are maintained in the Peer1 node. The Peer2 node has joined Channel1 and Channel2, so the Peer2 node maintains the ledger of the two channels, and so on. The channels and accounts that the node joins are one-to-one. This design enables data transactions to be performed simultaneously for each node of each body during the transaction process, and data transactions of all nodes in all channels can also be concurrently performed. Compared with the usual single-chain structure platform, this design can realize transaction parallelization under the premise of ensuring transaction data privacy, improved data throughput, of the whole network, and faster transactions.  
Figure 8: Schematic diagram of channel permission control mechanism.