Research On The Access Control Mechanism Of The Internet Of Things Based On Blockchain

With the rapid development of the Internet of Things(Io T),how to manage the data and services provided by Io T devices in a more secure way has become an important challenge.Access control is one of the most widely used security technologies.The traditional Io T access control scheme mainly adopts static and centralized architecture,which does not meet a large number of IoT devices,does not support the mobility scenario in which nodes can join and leave the network at any time.In addition,Io T devices are limited in terms of computing power,memory,and energy availability,so we need lightweight access control solutions with low latency.To overcome these problems,this paper creates distributed access control mechanisms for the IoT based on blockchain technology.The main research contents are as follows:(1)In order to solve the scalability problem of device access management in the IoT,we propose a distributed and lightweight access control system based on blockchain technology.Since Io T devices are resource-constrained,most IoT devices cannot store blockchain information.Therefore,the system's blockchain network does not include Io T devices,but defines a new node called the management hub,which requests access control information from the blockchain on behalf of the Io T devices.In addition,the solution involves a smart contract that defines all operations allowed in the access control system.The contract is unique and cannot be deleted from the system.The architecture is based on proof-of-concept and evaluated in actual IoT scenarios.The results show that blockchain technology can be used as access management technology in specific scalable IoT scenarios.(2)In order to implement the distributed and trusted access control for the IoT system,we propose a decentralized access control framework based on smart contracts.The framework consists of multiple Access Control Contracts(ACC),a Judge Contract(JC)and a Register Contract(RC).In this framework,each ACC provides an access control method for a subject-object pair.This method implements static verification by checking predefined policies,and implements dynamic verification by checking the behavior of the subject.ACC also provides functions to add,update,and delete access control policies.Once called by the access control subject,ACC will be run and verified by most participants in the system,thus ensuring the credibility of the access control.In order to facilitate the dynamic verification of ACC,JC provides a misbehavior judgment method,which receives the misbehavior report of the ACC subject,judges the misbehavior and returns the corresponding punishment.In order to manage access control and misbehavior judgment methods,RC registers method information(name,subject,object,and smart contract),and provides functions to register new methods and updateor delete existing methods.To demonstrate the application of the framework,a case study is provided to implement access control of an IoT system composed of a desktop computer,a notebook computer,and two Raspberry Pi single-board computers.The case study proves the feasibility of the proposed framework in achieving distributed and trusted access control of the IoT.