**1. Introduction**

The 4th Industrial revolution (4IR) is the current era where industry is driven by technology. It encourages the co-operation between scientific knowledge and experience with business mindset and requirements. The key technologies that allow 4IR to be sustained are additive manufacturing techniques, Autonomous and collaborative robotics, Industrial Internet of Things (IIoT), Big data analytics, Cloud Manufacturing techniques [1]. The current scenarios show the benefits of IIoT in improving QoS industries, starting from predictive maintenance, reaching remote controlling of assets, and deploying Digital Twin concept that allows virtualizing the operations environment and permits the owner to be proactive when any anomalies are detected [2]. Even though IIoT adds value to the traditional industry, there should be a balance between the operational benefits and the security level.

Aims and objectives

<sup>•</sup> To study and compare the existing IoT architectures


This chapter is designed to be used as a reference to study the effectiveness of Artificial intelligence (AI) and to enhance the security techniques for mitigating the threats faced by IIoT deployment. Section 2.1 discusses IoT architecture and Section 2.2 demonstrates the IoT security challenges. Section 2.3 describes the main AI categories and their subcategories. It also points out the appropriate and relevant situation to employ AI categories based on the available data and the type of intelligence needed. Section 3 explores IIoT details, its significant business model, and the added values. Section 4 focuses on IoT security in terms of threat model, threats classification, and common IoT security mitigations. This chapter ends with a comparative study of AI categories used to mitigate IIoT security challenges in Section 5.
