Subsidy Bridge: Rewarding Cross-Blockchain Relayers with Subsidy.

Cross-chain technology aims to enable interoperability between isolated blockchains. However, existing cross-chain solutions cannot achieve both decentralization and incentive compatibility. In the paper, we introduce Subsidy Bridge, a general and decentralized relay scheme with special incentive design similar to Bitcoin mining. In Subsidy Bridge, target chain carries out cross-chain validation relying on relayers submitting new block headers of source chain, while honest relayers obtain basic subsidy from target chain and transaction fee from cross-chain users. The utility of honest relayers is always positive even when users are temporarily inactive. Analysis results demonstrate that our solution can provide decentralization, incentive compatibility, and strong security.