Leveraging Zero-Knowledge Proofs for Blockchain Interoperability: Experiences with Ethereum and Hyperledger Fabric

Zero-knowledge proofs (zkp) have been used to address several blockchain limitations (e.g. privacy, scalability). Recent work has proposed its usage to improve blockchain interoperability solutions, aiming to help software architects and developers reduce barriers to blockchain adoption. However, more studies are needed to understand the full potential of zkp in this context. In this paper, we empirically analyse how zkp may improve a gateway-based solution for blockchain interoperability. The results showed that it was possible to improve the selected solution in terms of privacy and data confidentiality limitations, by incorporating anonymous cross-chain authentication and private data exchange. A prototype was developed and evaluated using three strategies: 1) its application in a use case scenario, 2) performance tests, and 3) cost analysis. The evaluation showed that the approach is technically feasible, but not suitable for every use case. Furthermore, the private data exchange approach confirmed the results of other studies: zkp is not mature enough for some scenarios, and more work is required in this area.