# A Trust-Based Predictive Model for Mobile Ad Hoc Network in Internet of Things +
## 1 Introduction  
The Internet of things (IoT) is a heterogeneous network of physical devices, vehicles, home appliances, and other objects embedded with electronics, software, sensors, actuators, and connectivity. By enabling seamless connection between objects and the rapid exchange of large volumes of data, this paradigm offers a new class of advanced services characterized by being available irrespective of time, place, and person. It may comprise different types of wireless networks such as wireless sensor networks (WSNs), ZigBee, Wi-Fi, mobile ad hoc networks (MANETs), and RFID. The deployment of IoT devices grew significantly in present years. This includes buildings (homes, schools, offices, factories, etc. ), utility networks (electricity, gas, water, etc. ), transportation networks (roads, railways, airports, harbors, etc. ), transportation vehicles (cars, rails, planes, etc. ), healthcare systems, information technology networks, and so on. The use of wireless networks makes the physical infrastructures more smart, secure, reliable, and the systems become fully automated. IoT collects, stores, and exchanges a large amount of heterogeneous data from different types of networks and provides critical services in healthcare, manufacturing, and utility networks. Mobile Ad hoc Network (MANET) is a distributed collection of wireless nodes which can work without the presence of any centralized administration or fixed network infrastructure. In this network,the nodes are free to move randomly at any given time. The mobility of nodes can vary from almost stationary to constantly moving nodes. Thus, the topology of the network and interconnections between the nodes can change rapidly and unpredictably. In MANET, the nodes within the radio range can immediately communicate with each other, whereas the nodes that are not within each other's radio range are able to communicate with the help of intermediate nodes where the packets are relayed from source to destination. Therefore, the nodes in a MANET have to co-operate among themselves for the multi-hop communications. Security is a prime issue in MANET due to weak connectivity, resource constraints, and limited physical protection of the mobile nodes. Therefore, MANETs are more prone to attacks than infrastructure-based networks. Establishing secure communication in a MANET is particularly challenging because of (i) shared wireless medium; (ii) no clear line of defense; (iii) self-organizing and dynamic network; (iv) most of the messages are broadcasted; (v) messages travel in a hop-by-hop manner; and (vi) nodes are constrained in terms of computation and battery power. Trust can play an important role to improve security of ad hoc networks by a-priori or run-time evaluation of trustworthiness of its peers before making any routing decision. Due to resource (e.g., energy, bandwidth) constraints, all the nodes may not take part in routing and subsequently they do not forward data packets. To ensure the availability of the nodes and provide secure end-to-end communications between them, the trustworthiness of a node is a good measure. Cryptographic mechanisms cannot help in order to detect/prevent such random behaviors which pose security threats to the network. The notion of trust management does not replace cryptography, but rather supplements to it. Cryptography and a trust decision framework can work hand-in-hand to achieve holistic security in IoT-MANET. In order to ensure reliable, secure, and timely delivery of packets in the network, the present work has designed and developed an evidence/behavior-based trust framework in a cluster-based IoT-MANET. The nodes of the IoT-MANET are grouped into one-hop clusters [1; 2] and a predictive trust management model is developed for trust calculation and propagation. This model is well suited for detecting malicious nodes and improving the performance of the network. Trust is sociological concept first defined by [PERSON] [3].