## 2 Related Survey Papers  
In line with the increasing concerns regarding LPWAN and IoT security vulnerabilities, several survey works have presented detailed description of LPWAN challenges and mitigation methodologies. This section presents some of the recent works in the literature.  
The authors in [15; 18] presented a brief survey on LPWAN, specifically on LoRaWAN security. The authors discussed some possible attacks in the LPWAN and mentioned a few solutions for their mitigation. [PERSON] [23] presented a survey on security issues precisely on LoRa and LoRaWAN. The author emphasized that the prevention of LoRa and LoRaWAN attacks require the application of good key management practices. By focusing on key management problems, the author suggested that efficient solutions need to be developed in order to prevent the end user from cyberattacks and hacking. The authors in [24] presented a survey on the deployment of LoRaWAN for IoT communication focusing on the physical and network layer of the LPWAN standard. The authors identified some LoRaWAN challenges, possible improvements and extensions to the LoRa and LoRaWAN standard. In a similar LoRaWAN study, the authors in [16] presented a security risk analysis of LoRaWAN using European Telecommunications Standards Institute (ETSI) guidelines. The work analyzes LoRaWAN v1.1 threat scales and impacts.  
The authors in [25] conducted a detailed survey of IoT security. The authors suggested that software defined network (SDN) and block chain should be employed to address the issue of key management, confidentiality, integrity, and privacy in IoT systems. They highlighted the benefits that blockchain and SDN can bring to the IoT security in terms of flexibility and scalability. The article only focused on SDN and blockchain domain. Similarly, the authors in [26] presented major security issues in IoT. The authors discussed and categorized security attacks based on the IoT layered architecture. They briefly discussed the mechanisms suggested in the literature for leveraging IoT security at different levels. Furthermore, the authors referred to some open research challenges in IoT security. The work presented in [27] focused on various attacks that can take place on different layers of IoT. The authors discussed some security mechanisms which can detect and prevent the attacks. In a similar study, the authors in [28] presented a survey on security and privacy issues in IoT architectural layers (the perception, network, transport, and application layer). The authors discussed the limitations of IoT devices especially in battery and computing resources and possible solutions are discussed. The authors in [29] presented a survey on security threats at different IoT layers. The authors discussed some security solutions such as blockchain, machine learning, edge and fog computing. Similarly, the authors in [30] presented a survey on IoT security issues. The authors presented a comprehensive analysis highlighting the security goals, attacks and solutions. The authors in [31] present an overview about different layered architectures of IoT and attacks regarding security from the perspective of layers. The authors also review mechanisms that provide solutions to these issues with their limitations. Furthermore, they suggested a new secure layered architecture of IoT to overcome these issues.  
In general, these survey papers highlighted some state-of-the-art analysis of IoT and LPWAN security. However, the survey works do not cover most of the threats and security challenges that are attributed to LPWAN. Thus, this paper fills the research gap by bringing together a wide range of LPWAN security challenges, the methodologies employed in mitigating security attacks and research future directions.