While studying the scenarios of sensitive data cross-domain sharing, we found there was no security assessment of smart contracts within existing data sharing schemes, which might lead to data leakage or unauthorized data access. To address this issue, we proposed a comprehensive security assessment of the smart contracts involved in existing data sharing solutions. In which, we extended the current smart contract tools to include detection capabilities for 7 additional types of vulnerabilities and implemented automatic repair functions for smart contracts. We also designed 3 types of smart contracts for the Hyperledger Fabric platform to facilitate sensitive data cross-domain sharing, specifically for data upload, data access, and data management functions to make sure that complex vulnerabilities could be automatically repaired. In our designation, the smart contracts for data upload and data access utilize the CP-ABE method and the data management smart contract includes various functions for secure management and tracing of data on the blockchain, which collectively ensure the security and comprehensive functionality of sensitive data cross-domain sharing scheme.

Blockchain systems encompass many distinct and autonomous entities, each utilizing its own self-contained identity authentication algorithm. Unlike identity authentication within a singular blockchain, cross-chain scenarios demand special attention due to their pivotal role in enabling the acknowledgment of users’ identities across diverse domains. This capability is the foundational prerequisite for the circulation of resources across different chains. Consequently, the central challenge for cross-chain systems lies in establishing mutual recognition and trust in users’ digital identities. This paper proposes a Multi-User Proxy Re-Signature (MU-PRS) algorithm, facilitating the cross-chain conversion of signatures from multiple users. Concurrently, This paper propose the Multi-Notary Signature Conversion (MN-SC) mechanism, designed to address the challenge posed by disparate system mechanisms across blockchains during cross-chain authentication. Leveraging the MU-PRS algorithm and MN-SC mechanism, we present a Multi-User Cross-Chain Authentication Scheme (MU-CCAS) within a heterogeneous blockchain environment. This scheme enables the verification of identities of multiple cross-chain users through a single signature verification. This innovative approach not only addresses the centralization issues inherent in third-party cross-chain authentication but also significantly enhances the efficiency of identity authentication. The evaluation results demonstrate MU-CCAS’s superior security over existing solutions in three dimensions: BAN logic, Scyther verification, and security attribute analysis. Additionally, it establishes that MU-PRS and MU-CCAS have low computational overhead, easy implementation, and excel in algorithm, scheme, and cross-chain performance. Overall, our work provides a robust and efficient framework for cross-chain authentication, addressing centralization challenges and enhancing digital security.