  With the rapid development of blockchain technology, different types of
blockchains are adopted and interoperability across blockchains has received
widespread attention. There have been many cross-chain solutions proposed in
recent years, including notary scheme, sidechain, and relay chain. However,
most of the existing platforms do not take confidentiality into account,
although privacy has become an important concern for blockchain. In this paper,
we present TrustCross, a privacy-preserving cross-chain platform to enable
confidential interoperability across blockchains. The key insight behind
TrustCross is to encrypt cross-chain communication data on the relay chain with
the assistance of trusted execution environment and employ fine-grained access
control to protect user privacy. Our experimental results show that TrustCross
achieves reasonable latency and high scalability on the contract calls across
heterogeneous blockchains.
