# A Cross-Chain Solution to Connect Multiple DNS Blockchains in Consensus Roots System
## 4 Construction of Our System  
### Proposed System  
This system uses a 1 + N main-subchain cross-chain architecture. The relay platform is the core component of the system. It connects blockchains with cross-chain needs as subchains, and it handles multiple tasks in the cross-chain process. The system also uses a staged transaction atomic exchange protocol, which is deployed on the relay chain. In this model, smart contracts implement the process of staged transaction atomic exchange. This architecture can enable multiple heterogeneous blockchains to cooperate and realize cross-chain transactions, while the relay platform acts as a reliable intermediary, which can improve the security and reliability of transactions. This allows different regional DNS blockchains to interoperate and connect. The cross-chain solution designed in this paper has many details, such as blockchain node identity authentication, cross-chain message transmission and processing, smart contract execution, etc. These details form a complete cross-chain solution. Figures 3 and 4 show the cross-chain solution's overall architecture and the atomic exchange transaction in the cross-chain interaction process, respectively. Assuming that the DNS blockchain of Region A wants to synchronize a domain name information with the DNS blockchain of Region B, then this example illustrates the more detailed cross-chain synchronization domain name process of the cross-chain system. The complete cross-chain process of this scheme is as follows. 1. The A subchain submits a cross-chain request to the main chain, asking to synchronize DNS records with the B subchain. It includes its own identity, the B subchain's identity, and the target domain name, and it then forwards this information to the A verification node. The A verification node first confirms that the A subchain is registered in the consensus root system. 2. Upon successful validation, the A verification node relays the cross-chain request to the B verification node on the main chain, carrying the same identity and domain name data. 3. The B verification node authenticates the request origin via the relay platform and then forwards it to the B subchain for processing. 4. The B subchain evaluates the request and decides whether to assist with DNS resolution. If it agrees, it returns the resolved record along with its identity to the B verification node; if not, it sends a rejection message, which the B verification node  
Figure 4: Our blockchain-based DNS cross-chain solution. Figure 3: Atomic deal swaps. relays back to the A subchain. This exchange constitutes the negotiation phase of a simple atomic-swap protocol. * The B verification node verifies that the response originates from the B subchain and forwards the result to the A verification node on the main chain. * The A verification node authenticates the response source and delivers it to the A subchain. * The A subchain checks that the response matches its original request and the intended transaction parameters, thereby completing both the transaction and verification phases of the atomic-swap protocol. It then sends a completion confirmation to the A verification node. * The main chain generates a cross-chain transaction proof, recording the two blockchain identifiers, the synchronized DNS data, and the timestamp of completion. This proof is immutably stored on-chain, marking the end of the DNS synchronization process. To ensure valid cross-chain information, the verification nodes utilize consortium blockchain identity authentication. In domain name cross-chain synchronization, the main chain employs Hyperledger Fabric's channel mechanism [26] for secure communication and faster verification, enhancing efficiency. This approach integrates cross-chain processes into the consortium blockchain, improving security and reliability. It also introduces phased atomic exchange transactions for DNS domain name synchronization, offering a flexible and secure choice for the consensus roots system.