A Flexible and Privacy-preserving Cross-chain Identity Authentication System based on Anonymous Credentials

Identity authentication plays a crucial role in achieving secure cross-chain interoperability. However, the use of various network architectures and consensus mechanisms in different blockchain platforms leads to interoperability challenges among blockchains, resulting in difficulties with identity authentication. Moreover, identity authentication frequently encounters challenges related to privacy leakage. To address these issues, we propose a flexible and privacy-preserving identity authentication system based on anonymous credentials. Specifically, We employ relay chain technology to construct a cross-chain identity authentication framework that enables data flow between different blockchain networks. The system utilizes Merkle tree to construct the credential list stored on the blockchain without requiring the credential issuer to hold the signing key and employ zk-snarks to achieve credential anonymity for privacy-preserving. Additionally, we leverage Blind Groth16 technology to enable flexible modification of access standards during identity authentication. A security analysis demonstrates that our system can protect the privacy of user identity information during identity authentication. Extensive experiments conducted on BitXHub showcase the availability and flexibility of our system.