Research on key technologies for privacy-preserving, regulatorily compliant, and cross-chain interoperability in heterogeneous blockchain systems.

With the development of blockchain technology, the issue of "value isolation, " caused by ecological heterogeneity, is becoming increasingly important. Interaction between blockchains has proven to be an important foundation for building the Internet of Value. However, existing solutions struggle to simultaneously meet user demands for transaction confidentiality and regulatory compliance and often suffer from risks of centralization, loss of private data, and regulatory inefficiency. To address these issues, this paper proposes a new paradigm and universal framework for ensuring confidentiality and cross-chain compatibility in heterogeneous blockchains in compliance with regulatory requirements. There are three main contributions of this work: First, the distributed threshold network (DTN) has been designed as a reliable foundation that reduces reliance on a single authority through threshold signature technology, thereby increasing system security and reliability. Second, multi-party computation (MPC) is innovatively integrated into the inter-network process and form the privacy-preserving verification protocol (PPVP), which allows nodes to verify the authenticity of transactions without openly revealing data, ensuring confidentiality by default. Third, a key-shared supervision protocol (KSSP) is being developed that makes regulatory bodies participants in the MPC process. This allows for proper evaluation of suspicious transactions without decryption, fundamentally combining confidentiality and regulatory requirements. Theoretical analysis shows that the proposed system is resistant to existential forgery attacks under the random oracle model, while its basic protocols provide universal security (UC) and computational accuracy. Experimental validation consisted of implementing a prototype system and comparing it with existing solutions. The results show that the proposed solution maintains high performance (processing capacity > 1250 TPS, latency < 400 ms) while significantly outperforming existing approaches in terms of decentralization, confidentiality, and regulatory capabilities. This opens up a real technical path to creating a secure, reliable, and next-generation compliant blockchain Internet.