PXCrypto: A Regulated Privacy-Preserving Cross-Chain Transaction Scheme

The cross-chain technology is used to solve the problem of data islands between blockchains. Existing cross-chain techniques are challenging to resolve the conflict between transaction privacy and transaction regulation. Due to the decentralized nature of the blockchain, data on one chain are hard to get verified on another chain. Users cannot exchange across different heterogeneous chains without exposing transaction information. Also, cross-chain transactions increase the barrier to regulation from governments. To fill the gap, this paper proposes an innovative regulated privacy-preserving cross-chain transaction framework, called PXCrypto, which can achieve cross-chain transactions on any heterogeneous blockchain while regulating transactions and users’ identities. PXCrypto maps heterogeneous tokens to the PXCrypto consortium chain by presenting cross-chain asset proofs, and then uses the corresponding wrapped tokens for trading. The scheme leverages a proxy multi-party computation mechanism to achieve cross-chain confidential transactions using an order matching mode to protect the bid prices on transaction orders. PXCrypto conducts transaction-related calculations through a pre-elected committee to regulate these transactions through the regulatory authority. We implement the scheme and accordingly conduct the evaluations. The results prove its security, efficiency, and practicality.