Fig. 2
From: An access control model for the Internet of Things based on zero-knowledge token and blockchain
Network topology structure. The addresses of UUIDA and UUIDAgents accessing the device and gateway agents are stored in the local PC database, managed by the Web module configuration. After the gateway device is started, the Web module begins to listen on the port. When PC performs a read UUIDA operation, it needs to search the IP address of the reading device from the database and establish a socket connection to this address. After receiving the packet, the gateway agent sends the data to the router, which forwards the data to the corresponding node based on the contents of the routing table to invoke the smart contract on the blockchain. The blockchain node starts with an RPC address that is connected to the gateway through web3J's interface to perform the same operations as the client