A Decentralized Cross-Chain Service Protocol based on Notary Schemes and Hash-Locking

Yangyang Sun, Longyang Yi, Li Duan, Wei Wang

Abstract: With the rapid development of blockchain technology, its applications have been extended to various fields such as supply chains, the internet of things, and finance. However, different blockchains cannot directly interconnect due to discrepancies in the blockchain architecture, resulting in data islands. Cross-chain technologies are services that provide interoperability for different blockchains, enabling them to exchange data and transfer assets. This paper summarizes and analyzes cross-chain technologies of notary schemes, hash-locking, and relays. We find that the notary may be evil in notary schemes. Furthermore, hash-locking limits application scenarios that can only be used for assets exchange, and the relay is difficult to deploy in a real scenario. To overcome the drawbacks of existing technologies, we design a secure and fully functional cross-chain service protocol, which combines notary schemes with hash-locking, and introduces rewards and punishments. This proposed protocol is easy to deploy in a real scenario and solves the problem of evil notaries, as well as prevents the sore loser attack and the wormhole attack. Finally, we evaluate the proposed protocol and experimental results illustrate that it is more efficient than the BitXHub project, and is also fault-tolerant.