GAM: A scalable and efficient multi-chain data sharing scheme

Multi-chain data sharing refers to cross-chain data exchange among multiple blockchains. However, existing multi-chain data sharing schemes rely on direct blockchain-to-blockchain connections to establish links among multiple chains. This leads to poor scalability and low efficiency as the number of connected blockchains increases. To address these problems, we propose GAM (Group Authorization-based Multi-chain Data Sharing) for scalable and efficient multi-chain data sharing. GAM enhances scalability by organizing users from different chains into authorized virtual groups, enabling trusted data sharing within it. To further improve efficiency, the data sharing authorization process is executed on-chain, while data transfer is based on off-chain storage. We provide a formal analysis of GAM in multi-chain scenarios and implement a proof-of-concept prototype using Hyperledger Fabric. Experimental results demonstrate that GAM is effective in reducing the execution time of multi-chain data sharing while maintaining high transaction throughput and minimal end-to-end delay.