Design And Research Of Blockchain-based Smart Contract Model For Internet Of Things

In recent years,from small wearable smart watches to large spaceships,IoT technology has spread to every business and consumer field.The traditional structure of the IoT is becoming more and more complex,and the dynamic and massive nature of device interconnection leads to the instability,low security and poor authority allocation ability of device access in the traditional Internet of things,which indirectly leads to the security risks of device access.There is a security risk for access to the device.However,in the face of the above-mentioned shortcomings of the Internet of Things,the blockchain technology with the characteristics of decentralization and self-management has become the preferred technical solution for the IoT applications.The blockchain technology combines many new technologies such as cryptographic algorithms,smart contracts and peer-to-peer networks,which can fundamentally solve the deficiencies of the IoT.This thesis adopts blockchain with distributed structure,decentralization and information immutability as a trusted environment for device access and authentication in the IoT.First,the requirements analysis of the data security storage system of the IoT equipment is carried out,and a smart contract model of the IoT based on the blockchain(BC-SC model)is proposed,which adopts a blockchain peer-to peer distributed network structure to build a trusted transaction environment realize machine-to-machine(M2M)and human-to-machine mutual trust models.The BC-SC model divides the nodes in the network into primary nodes and secondary nodes according to storage capacity.The primary node completes the verification of the data in the network and distributes the key with the identity to the secondary node through the national secret SM9 algorithm to complete the M2 M two-way authentication,while the secondary node mainly completes data perception and stores transaction information only related to itself;in this model,a hybrid encryption method is used to achieve the authenticity of M2 M data and information;In this model,the authenticity of the information is achieved by using hybrid encryption;the consensus mechanism in the blockchain is used to ensure the legitimacy of nodes and avoid malicious nodes from stealing information,and implement smart devices are deployment based on the characteristics of flexible deployment feature of smart contracts to improve the entire system security.Finally,this thesis selects the shared charging pile as the verification scenario of BC-SC model,and completes the deployment and invocation of the blockchain smart contract through the simulation scenario,through model comparison and performance analysis,it is concluded that the BC-SC model is between devices in the embedded environment.The interaction is relatively safe and reliable.