A privacy-preserving method for cross-chain interoperability using homomorphic encryption

Cross-chain technology mitigates the interoperability challenges between disparate blockchains, facilitating communication and information sharing. However, the evolution of cross-chain technology has brought forward privacy concerns that require immediate attention. Cross-chain transactions involve the participation of various blockchain networks, thereby introducing potential risks of sensitive information exposure. We propose a privacy protection method for blockchain interoperability through the utilization of homomorphic encryption. By enabling computations to be carried out on encrypted data, our method ensures the correctness of cross-chain transactions while simultaneously upholding the confidentiality of sensitive information. We apply our proposed privacy-preserving method for Hash Time-Locked Contract and Relay cross-chain technologies, named PTLC and PRC, respectively. To validate the effectiveness of our method, the experiments of both applications are performed on two distinct blockchain networks to simulate the process of cross-chain. The experimental results indicate that our method can ensure that asset exchange and data interactions are carried out securely without compromising the confidentiality of relevant information.