Research On Blockchain-Based Access Control For The Internet Of Things

With the continuous development of the Internet of Things(IoT)technology,more and more intelligent devices have joined the network,and the IoT has entered the era of information explosion.As a result,information security issues in the IoT have gradually become the focus of attention.Access control technology is one of the key technologies to ensure the security of the IoT information.It can prohibit illegal users from accessing the IoT information,and at the same time restrict legal users to only access information within their authority.This paper studies traditional access control models and concludes that most of these models are built on central trusted entities.For the rapidly increasing number of IoT devices,the central trusted entity faces huge management and maintenance pressures,which easily cause single points of failure.The emergence of blockchain technology provides a solution for establishing mutual trust among entities in the open IoT environment.Blockchain has the characteristics of decentralization and non-tampering.Using blockchain and traditional access control model to study a decentralized access control model has become a new research direction.Attribute-based access control model uses attributes to distinguish entities in the system,and uses the relationship between entity attributes to standardize access control policies,which can realize dynamic and fine-grained access control.This paper studies blockchain technology and Ethereum technology.Ethereum solves the problem of insufficient scalability of the Bitcoin blockchain.The introduction of smart contracts has enhanced the computing power of the blockchain.So this paper chooses Ethereum and attribute-based access control model to build a new decentralized model.The model consists of five function points(device registration point,attribute information management point,contract information management point,permission decision point and access control enforcement point)and two types of smart contracts(policy contracts and permission decision contract).The model uses attribute information as the key element of access control judgment,and stores key attribute information on the blockchain to prevent malicious nodes from tampering with it.Based on this model,an IoT access control system is implemented,which consists of an access control module,a security monitoring module,and a web management module.Among them,the access control module is an implementation of the access control model;the security monitoring module is responsible for monitoring the behavior in the access control process and giving timely punishment measures for malicious devices;the web management module is responsible for managing and maintaining basic data in the IoT environment,and at the same time able to view access logs of security monitoring modules and punish device information.Finally,a home IoT environment is simulated to test and analyze the system model.The availability of the access control model and the robustness of the security mechanism in the system are tested respectively.The test and analysis results meet the expected requirements.Experiments show that the proposed blockchain-based access control model can achieve decentralized access control in the dynamic IoT environment,and the security mechanism can ensure the robustness of the system.