# Blockchain-Based Internet of Things Access Control Technology in Intelligent Manufacturing
###### Abstract  
The integration of information systems and physical systems is the development trend of today's manufacturing industry. Intelligent manufacturing is a new model of manufacturing, based on advanced manufacturing technology with human-machine-material collaboration. Internet of Things technology is the core technology of intelligent manufacturing, and access control technology is one of the main measures to ensure the security of the IoT. In view of the problem that the existing IoT access control model does not support distributed and fine-grained dynamic access control, this paper uses the characteristics of blockchain, such as decentralization and non-tampering, combined with the attribute-based access control (ABAC) method, to propose a distributed access control method, applicable to the IoT environment in the process of intelligent manufacturing. This paper describes a fine-grained access control policy by defining the access control attribute values in a formal language, which supports complex logic operations in the policy and enhances the expressiveness of the model. Distributed access control decision making, using smart contracts for blockchain, improves the decision-making efficiency of the access control model, increases the post-facto audit of the access control behavior, and improves the overall security of IoT data protection. The paper concludes with proof of security and a performance analysis, and the experimental results, such as storage and computing overheads, show that this method can provide fine-grained, dynamic, and distributed access control for devices in intelligent manufacturing, ensuring the security and reliability of access control for IoT devices. accs control; blockchain; IoT; intelligent manufacturing +
Footnote †: journal: Applied  
fields that are interconnected and collaborated. As the scale of the IoT continues to grow, the probability of collaboration scenarios between devices is increasing [4], especially in the process of digital twin technology. A large number of applications, the entire intelligent manufacturing model, integrate a large number of historical and real-time process data from physical systems. Digital agency needs to monitor the production system or the state of the process, predict the performance of the system, and generate the system behavior or control action; data exchange and data access control put forward higher requirements [5]. Blockchain-based and green Internet of Things' UAV applications [6], as well as blockchain-based face monitoring by drones (used during COVID-19), also face a lot of data access control requirements [7]. In order to ensure security, collaboration between different types of devices should be performed with appropriate access control, according to the security and privacy protection characteristics of the devices. As a basic mechanism for achieving security in information systems, access control (AC) determines the communication rights between authorized subjects and objects, according to specific security models and policies [8]. An effective access control mechanism can meet the information security requirements, such as system confidentiality, integrity, and availability. For the scenario of the collaboration of IoT devices in intelligent manufacturing, this paper proposes an AC method applicable to the IoT environment. The access control policy is described in a fine-grained manner, using attributes that support complex logic operations in the policy and enhance the expressiveness of the model; the distributed access control determination decision, using smart contracts deployed on the blockchain, improves the decision-making efficiency of the model AC and enhances the IoT data security. Lightweight nodes in the blockchain are introduced to adapt to the complex and diverse heterogeneous devices in the IoT, to enhance the scalability of the system [9]. This article analyzes the deficiencies of access control technology research in the current intelligent manufacturing Internet of Things environment.