# Secure Data of Industrial Internet of Things in a Cement Factory Based on a Blockchain Technology
## 1 Introduction  
Recent revolutions in the industrial sector have come from innovative technological concepts such as big data, cloud computing, artificial intelligence, and cyber-physical systems. Merging the smart industry with Internet of Things (IoT) technology has given rise to new and diverse requirements to ensure a secure industrial environment [1]. With these technologies, the industrial process has evolved in new directions related to the provision of facilities, reducing production costs, and increasing production rates. The Fourth Industrial Revolution will be achieved by linking conventional industrial environments to internet networks [2, 3].  
Traditional IoT depends on the use of a centralized architecture, with information processing and analysis facilities provided by cloud-based servers. Each expansion in the use of IIoT networks is accompanied by renewed security and privacy challenges.  
The main drawback of a centralized architecture is that it represents a bottleneck, latency, and a single point of failure, meaning that hacking can lead to the whole network going down [4]. The use of a centralized architecture therefore becomes unsuitable, especially for high-performance applications [5]. In the new IIoT, the amounts of sensor data are huge, and this would lead to a significant increase in the load on centralized verification systems. However, in the IIoT, challenges related to security and scalability can be overcome through the integration of blockchain technology with IoT devices [6].  
The blockchain is an important technology that can provide a high level of secrecy, privacy and protection for control systems in real-time [7,8]. It is a distributed, decentralized, timestamp, and shared database ledger. That has ability to store the identity of registered nodes and all transactions between peers, cryptographic techniques and a hash algorithm are used to secure the transactions and authenticate the peers without the need for trusted third party services, blockchain uses hashing function (SHA-256) and elliptic curve cryptography (ECC) to provide robust cryptographic proof for data integrity and authenticity. Therefore, blockchain technology has unique advantages over other conventional technologies [6]. In addition, the most common problems associated with a centralized architecture can be solved through the use of a decentralized system. Blockchain technology can also help to improve the performance of IIoT platforms in various areas of application [9].  
Blockchain features, such as distributed ledger, distributed database, distributed consensus mechanism, transparent log, timestamp, and traceability provide a trusted system that can efficiently resist many types of cybersecurity attacks [10]. By merging the blockchain technology and exploiting its features in a new environment (founded on industrial IoTs), we ensure the system's security and data integrity during the autonomous transfer of data between machines (M2M) in an industrial environment. This merging helps increase the possibility of a robotic control system with the remote observation of machine events, to make the right decisions in time. With our proposed architecture (depicted in Figure 1), we integrated the technology of blockchain, smart contract and IoTs in a cement factory as an industrial environment. Our proposed architecture consists of three layers: Physical, Blockchain Service and Application. These layers work together to build a lightweight security scheme by utilizing STM32 boards and a low-power STM32F427 processor. Moreover, adopting a fast, highly scalable, low energy proof of authentication (PoAh) as a consensus mechanism helps to enhance the computational performance [10,11].