Research And Implementation Of Internet Of Things Access Control Mechanism Based On Blockchain

With the rapid development of the Internet of Things,intelligent interconnected things came into being.Objects can communicate with each other through the Internet of Things,and applications and services have brought about a qualitative improvement in our quality of life.The Internet of Things system deals with massive data,including health,finance,location and other information,which is very sensitive.Therefore,data security management in the Internet of Things needs effective access control.As a subset of the Internet of Things to build an intelligent transportation system,the Internet of Vehicles has revolutionized the technology of smart cars,but there are also many communication security problems.If the Internet of Vehicle system is infiltrated by malicious or unauthorized nodes,the authenticity,accessibility and privacy of shared resources will be damaged.There are still some shortcomings in the access control of the existing Internet of Things system.For example,centralized,cloud-centric Internet of Things systems rely on third-party organizations,which easily leads to a single point of failure;Static,the static characteristics of access control schemes are not conducive to adapting to the evolving risk attributes;Coarse-grained,coarse-grained access strategy in the Internet of Things,can not guarantee the accuracy of data resources.As a new decentralized distributed system,blockchain technology shows the characteristics of traceability,openness and transparency in digital asset management.The smart contract supported by blockchain technology provides automation of services and enhances the security and confidentiality of the system.Aiming at the above problems and key technologies,this thesis studies the access control mechanism of Internet of Things based on blockchain.The main research work and achievements are as follows:(1)Through in-depth analysis of the access control principles and solutions in the existing Internet of Things system,a Blockchian-based General scheme for Access control in Internet of thing(BGAI)is proposed.This scheme combines blockchain technology,Inter Planetary File System and attribute-based encryption technology,and designs a decentralized distributed storage system,which overcomes the system defects of cloud-centric Internet of Things,such as single point of failure,high delay and high storage cost.By combining edge computing with cloud computing,a new hybrid computing model is proposed to improve the low latency tolerance of real-time data.In addition,the edge device establishes a keyword index for shared data and performs keyword search through smart contracts,which solves the problem that traditional cloud storage may not return results honestly.(2)Based on the above architecture,a specific distributed access control scenario is considered.Aiming at the field of vehicle networking,an intelligent traffic adaptive control scheme based on smart contract is proposed.The scheme integrates consortium blockchain and smart contract technology,constructs a distributed trusted platform,and provides a secure communication environment for intelligent transportation systems.Edge computing is introduced into the three-tier intelligent transportation system,which better solves the problem of delay tolerance of traffic data.The Webster algorithm is improved,and the queue length of vehicles is introduced into the improved algorithm to optimize the dynamic allocation of traffic lights.In this thesis,the Hyperledger Fabric is selected to build the blockchain architecture,and a series of performance analysis of the system is carried out.Experimental evaluation shows that the access request and response of this system perform well in time delay and throughput,and achieve fine-grained access control.