Today,cryptocurrency is a hot topic in industry and academia.As one of the most successful cryptocurrencies,Bitcoin reached $10 billion in the capital market in 2016.Blockchain is the core technology of cryptocurrency.It has the characteristics of decentralization and trust,and all transactions are stored in the block list.With these features,blockchain can greatly save costs and improve efficiency.With the rapid development of the Internet of Things,the environmental monitoring system has greatly improved the efficiency and transparency of the government's daily operation.However,most existing environmental monitoring systems currently provide services in a centralized manner and rely heavily on human control.Highly centralized system architectures are vulnerable to external attacks.In addition,it is relatively easy for criminals to destroy the authenticity of data,resulting in the public trust in environmental monitoring data is not high.To resolve these problems,this paper proposes an environmental monitoring data transmission scheme based on blockchain.The data acquired by the monitoring device is delivered to the data collection terminal by signature,and the data collection terminal verifies the data and writes it to the blockchain.Smart contracts analyze the data in real time and then issue the results.Taking PM2.5 monitoring as an example,the application of environmental monitoring blockchain system architecture in PM2.5 data transmission is discussed.Hyperledger Fabric is used to build the environmental monitoring blockchain,and realize the release and query functions of environmental monitoring data.The introduction of blockchain will greatly improve the security and authenticity of data in environmental monitoring system,thus providing more reliable information for environmentally relevant scientific research and decision-making deployment.In the consortium blockchain,the practical Byzantine fault-tolerant consensus algorithm(Practical Byzantine Fault Tolerance,PBFT)reduces block validation time and eliminates resource consumption issues.In order to solve the problem of high communication overhead of PBFT algorithm,this paper also proposes a practical Byzantine fault-tolerant consensus mechanism based on grouping(Group Practical Byzantine Fault Tolerance,GPBFT)for the consortium blockchain with authorized access mechanism.The GPBFT algorithm reduces the number of interactions in the consensus-achieving process by improving the traditional PBFT algorithm,thereby reducing the communication overhead in the consensus process.The GPBFT algorithm was tested using Prism.The experimental results show that the GPBFT algorithm can reduce the time of transaction confirmation and reduce communication overhead.The comparison of fault-tolerant capability analysis and consensus scheme shows that the GPBFT algorithm not only preserves the security of the original algorithm,but also compensates for its high performance and availability defects,so that the GPBFT algorithm can be applied to a larger-scale alliance blockchain system. |