# Utilising Acknowledge for the Trust in Wireless Sensor Networks
## 1 Introduction  
The standardization process for the Narrowband Internet of Things (NB-IoT) has been completed, and Wireless Sensor Networks (WSNs) are being considered as a critical component for sensing and collecting information [1]. WSNs are collections of hundreds of thousands of tiny devices with integrated sensing and wireless communication capabilities that are connected together, forming a wireless network. As a result of their limited or no mobility, they are considered a special case of ad hoc networks [2]. Several essential features of sensor networks are similar to those of Mobile Ad Hoc Networks (MANETs). For example, both require self-organization and wireless multihop operations, as well as time-variability in topology [3]. WSNs, which offer sensed information in context-aware and customized applications, have been extensively utilized in various areas, including intelligent connected vehicles, intelligent transportation, smart cities, precision agriculture, and environmental monitoring [4; 5; 6]. Because of the nature of the wireless medium, limited resources, and the sensors' natural cooperation, WSNs are vulnerable to several attacks (either self or malicious attacks,i.e., misbehaving nodes). Customers do not want to share their information with unauthorized persons since the data may be misused. This additional consideration is of greater importance in wireless environments, because anybody may eavesdrop on unencrypted communication. For that, both external and interior security threats are significant threats to information security in WSNs. Creating a secure path in these networks must guarantee that all nodes used to send data packets are trusted nodes. Therefore, it is necessary to build an efficient trust model; where the node can evaluate the trustiness of all neighboring sensor nodes through the interaction between them. The ability to make decisions in a WSN is critical for carrying out specific tasks since it assists sensors in forming collaborative efforts. It is thus necessary to implement a smart trust management scheme to determine the trustworthiness of sensor nodes, differentiate between malicious and good nodes, and boost trusted nodes while reducing the trust of suspicious nodes. Developing trust among sensor nodes has been identified as a new method to improve security in wireless sensor networks. Because sensor nodes have limited resources, especially battery power, the amount of energy used by sensor nodes is critical. Since these networks are designed to operate unattended in hostile environments for several years, energy replenishment is almost impossible under these conditions. One of the most challenging design concerns in WSNs is having limited energy resources, which implies that choosing sensor nodes for tasks should be done carefully to help keep WSNs alive. The WSN might suffer from serious system performance reduction if an inappropriate node is selected as a routing node. As a result, selecting one or many appropriate nodes to act as cooperation partners for any node in a WSN is a difficult task. The overall system stability of WSNs may be enhanced by choosing the most suitable sensor node throughout the collaboration process. The contributions of this paper can be summarized as follows:  
1. Designing a new trusted routing technique for WSNs that uses first-hand and second-hand information and the acknowledgments (ACKs) from the data link and end-to-end TCP layers. 2. The protocol is proposed to detect and isolate the malicious sensors to create a freemalicious- end-to-end route, increasing the network's throughput and decreasing the network's energy consumption. 3. The proposed protocol performance is evaluated using different numbers of malicious sensors in the network and different network densities. 4. The proposed protocol is compared with existing BTRM and Peertrust models. To simplify reading the paper abbreviations, Table 1 summarizes all used terms.