Abstract: Aiming at the problems of malicious access, untrustworthy data sources, and identity forgery in the existing blockchainbased grain traceability model, a blockchain access control model for grain traceability based on a zerotrust mechanism is proposed. Based on the zerotrust security model and the concept of “never trust, always verify”, the blockchain is combined with tokenbased access control (TBAC). Using tokens as credentials to access resources, while introducing user trust analysis, establishing a dynamic and flexible authorization mechanism to achieve finegrained access control. Adding the blockchain smart contract to guarantee the automatic and trustworthy judgment of access control, TBAC is utilized to realize tokenbased access control; secondly, based on the user’s access behavior, Fuzzy Hierarchical Hierarchy Analysis (FAHP) is used so as to obtain the calculation method of the user’s trust value and to design the corresponding access control policy. Experimental results show that the method can correctly and efficiently respond to access requests, and dynamically grant users access rights on the basis of ensuring effective access to grain traceability data, realizing safe and reliable data access control.

Key words: zerotrust security, blockchain, access control, grain traceability, trust assessment

摘要： 针对现有基于区块链的粮食溯源模型中存在的恶意访问、数据来源不可信、身份伪造等问题，提出了一种基于零信任机制的粮食溯源区块链访问控制模型.以零信任安全模型为基础，贯穿“永不信任，始终验证”的理念，将区块链与基于令牌的访问控制(tokenbased access control, TBAC)相结合.以令牌作为访问资源的凭证，同时引入用户信任度分析，建立了动态灵活的授权机制，实现了细粒度的访问控制.加以区块链智能合约保证访问控制自动可信的判决，利用TBAC模型实现以令牌为基础的访问控制；其次，基于用户的访问行为，使用模糊层次分析法(FAHP)，从而得到用户信任值的计算方法，并设计相应的访问控制策略.实验结果表明，该方法能够正确、高效地响应访问请求，在保证粮食溯源数据有效访问的基础上动态授予用户访问权限，实现了安全可靠的数据访问控制.

关键词: 零信任安全, 区块链, 访问控制, 粮食溯源, 信任评估