基于区块链的农产品供应链可信追溯信息模型构建与原型系统验证

The agricultural product supply chain from "farm to plate" has such features as significant span in time and space and many concerned companies. It will cause many problems such as discontinuous tracking chain and unauthorized traceability information modification. Due to these problems, consumers now don’t trust in traceability information that they access through internet. So, the external agricultural products supply chain traceability based on block chain has become the key to solve the problems, which ensure traceability data authenticity and validity. The project aims to establish a credible traceability chain for agricultural products supply chain, including establish a traceability information model and technical framework for agricultural product block chain. Firstly the structure of traceability record based on Merkle tree algorithm is designed. The method of data storage and data link based on time stamp is constructed. Fundamentally, it ensures that the agricultural products traceability records cannot be tampered and faked. In the second part, The algorithm of public key/private key authentication of SM2 to solve the authenticity of the tracing responsibility body and the effectiveness of the information delivery. Based on the above research, PBFT algorithm for agricultural product traceability chain block efficient consensus mechanism will be designed for solving the problem of distributed track record consistency. Finally, an external traceability prototype system which takes brand agricultural products "Wuchang rice" as an example will be shown to verify the accuracy of the system monitoring the quantity changes in the supply chain. The traceability system theory and framework for agricultural products supply chain will be reconfigured in this project. And it will establish a credible foundation for traceability system in agricultural products supply chain.

从“农田到餐桌”的农产品供应链因时空跨度大、责任主体繁多，极易造成信息跟踪断链、信息被篡改等问题，消费者对追溯信息的真实性产生信任危机，基于区块链技术建立农产品追溯模型与系统成为解决问题的关键。本项目以解决农产品供应链可信追溯为切入点，构建农产品追溯区块链信息模型与技术框架。首先突破农产品追溯区块链数据模型，设计基于Merkle树的追溯记录结构，建立基于时间戳的链式追溯数据存储与链接方式，保证农产品追溯记录的不可篡改和不可伪造；在此基础上研究基于国密算法SM2的公钥/私钥身份认证方法，解决追溯责任主体的真实性和信息递的有效性；突破基于拜占庭容算法PBFT的农产品追溯区块链高效共识机制，解决分布式追溯记录一致性；最后拟以五常大米为例，建立基于区块链的外部追溯原型系统，并验证系统监控流通量变化的准确性。项目研究可重构农产品供应链追溯理论和技术框架，为建立可信的农产品供应链追溯奠定基础。

从“农田到餐桌”的农产品供应链因时空跨度大、责任主体繁多，极易造成信息跟踪断链、信息被篡改等问题，导致消费者对追溯信息的真实性产生信任危机。针对区块链追溯数据存储压力大，效率低问题，分析了供应链各环节关键数据，建立了基于Merkle树的农产品供应链追溯区块链模型，在此基础上，构建了“数据库+区块链”的链上链下追溯信息双存储结构，测试结果表明，当区块链追溯记录达到11万条，批次追溯记录为400时，相比传统的基于主键的查询方法，查询效率提高了70.56%；针对区块链追溯数据安全隐私保护和安全共享问题，研究了供应链追溯信息保护模型，构建了区块链追溯节点授权保护模型，建立了基于聚合签名算法的身份认证方法，测试结果表明，身份认证方法扩散性测试密文平均改变率为82.53%，相关性测试密文平均改变率为82.39%，具备较高的安全性与混淆性，解决了区块链隐私数据安全共享问题，提高了企业隐私数据的安全性；针对区块链追溯系统共识效率低和监管不透明的问题，改进了实用拜占庭容错算法，研究了区块链多链追溯监管方法，构建了面向追溯主体、追溯环节、追溯监管的区块链追溯系统监管模型，解决了区块链技术在供应链追溯中面临的监管合规、数据追溯和隐私保护等问题，提高了追溯系统的安全性，测试结果表明，系统吞吐量可达2500TPS；基于Hyperledger Fabric联盟区块链开发部署了农产品供应链区块链追溯系统（农信链），并在大米、小麦、杂粮、果蔬、畜禽、水产等多品类农产品追溯领域进行了探索应用，并已生成154613个区块，为农产品区块链可信追溯探明了方向。.项目申请发明专利11项，获得发明专利授权3项，发表学术论文15篇，其中SCI/EI论文11篇，获得软件著作权登记3项。通过项目执行，率先构建了基于区块链的农产品追溯模型，解决了农产品供应链追溯信息可信度低的问题，为建立可信的农产品供应链追溯奠定了基础；另一方面，本研究重构了目前农产品追溯的理论技术框架，具有广阔的推广应用前景。