# Efficient Secure Routing Mechanisms for the Low-Powered IoT Network: A Literature Review
## 1 Introduction  
IoT has been thriving as another global innovation in the last few years. It is expected that the world's fortunes will be changed by implementing IoT in various systems over the coming years. IoT will likely revolutionize the way we live today. The Internet of Things foundation was established to improve communication and data exchange between humans and devices for massive data transfer [1]. IoT's motivation involves the association of registering gadgets, mechanical and computerized objects, humans, and machines through applications utilizing the web interface and portable applications. The IoT climate can move information through an organization without expecting human-to-human or human-to-computer correspondence [2]. IoT is becoming a significant necessity for many industrial and communication technology applications. There has been an enormous increase in IoT implementation as it has been considered to have the massive number of 50 billion devices connected to the Internet by 2020 [3]. Furthermore, IoT applications designed to assist the disabled or elderly provideease and mobility at varying degrees of unconventionality for a reasonable price [4]. In addition, IoT adds to numerous fields, for example, agribusiness, climate, clinical areas, the educational sector, transportation, and finance. These innovations and upgrades improve our everyday lives [5]. Figure 1 shows the graph depicting the number of IoT devices in billions globally from 2018 to 2030 [6]. Numerous organizations and scientific research associations are working on various aspects of the IoT. They have presented a functional outline for the IoT's impacts on the economy and the vast majority of other existing fields over the next 10 years. Cisco is the primary organization that delivers numerous IoT undertakings, which included 24 billion smart objects by 2019. It is also expected that the Huawei company will introduce 100 billion IoT associations by 2025 [7; 8; 9]. Every second in the world, 127 devices are linked to the Internet. By 2020, out of all electronic device use, 63% will be using IoT technology. Of all the massive, smart city commercial projects, 23% consist of IoT implementation, while by the end of 2020, 40% of all healthcare organizations were embedding IoT [10]. Figure 2 depicts an analysis of the worldwide expenditure in billions of dollars on IoT from 2018 to 2023, which shows the cost of IoT is increasing day by day as enhancement in technology (such as automated machine systems, devices, etc.,) increases. In 2018 the expenditure was 616 billion USD, after that it increased slightly in 2019 and there was a significant change predicted for 2022-2023 [11]. Via controllers and cloud management, autonomy can be generated for the self-sufficiency and decision-making of nodes [12]. There is always a wide open door for intruders or hackers to utilize IoT devices for their potential benefit via various attacks, such as Denial-of-Service (DoS) attacks, phishing emails, and other unsafe worms or Trojans [13]. The IoT layers present multiple risks such as sniffing, spoofing, eavesdropping, and intrusion. IoT utilizes hubs, sensors, and intelligent recognition gadgets to gather  
Figure 1: Number of IoT devices in billions connected globally from the year 2018 to 2030 [6]. Figure 2: Worldwide expenditure on IoT from the year 2018–2023 [11]. information. Because of the nonappearance of verification administration, unapproved access can change data integrity or even erase the stored data [14; 15]. IoT systems can work under various conditions and, in most cases, have little computing capacity. Therefore, specific IoT devices can connect to many hubs, raising significant security concerns. As a result, security issues have proven to be more challenging to solve, as it is difficult to establish a nonexclusive security architecture or model [16].