Abstract: Electronic data management has emerged as a pivotal tool for government and corporate procurement in the process of modernizing material supply chains,which plays a decisive role in boosting market competitiveness and ensuring fairness in transactions.However,electronic procurement faces several challenges,especially during the bidding process.These include the varying credibility of diverse electronic data sources,the difficulty of protecting bidders’ privacy,and potential risks of collusion between bidders and procurers.Blockchain technology,with its decentralized structure,distributed ledger,and high transparency,aligns well with the distributed nature of participants in electronic procurement.To address these challenges,this paper proposes a privacy-preserving multi-entity cross-certificate authentication and access control model for material supply chains.The system utilizes smart contracts to maintain a trust list and employs efficient Merkle tree signatures for certificate issuance with minimal storage overhead.This ensures the trustworthiness of both certificate authorities and bidders,while optimizing the cross-domain certificate verification process,further enhancing the transparency and consistency of authentication.Additionally,the system employs attribute-based encryption to encrypt and store sensitive data from bidders.Fine-grained access control is implemented to allow only authorized procurers to access the necessary information,effectively preventing collusion risks before the bid opening and ensures fairness and transparency in the bidding process.Rigorous security analysis and simulation tests demonstrate that the proposed solution not only supports multi-entity cross-certificate system authentication,but also safeguards bidder privacy,providing flexible and robust access control.

Key words: Material supply chain, Cross-certificate system authentication, Smart contract, Privacy preservation, Attribute-based encryption