**1.1. Motivation**

In this work, we provide a reputation system based solution for routing security in WSN. We believe that such a solution approach is a feasible and applicable solution for the following reasons:


attacks will be tackled by modifications in the details of the module of interest that does not require a complete system revision. For example, a new attack might require adjusting the monitoring and detection phase without touching other parts of the system. WSN are deployed in very hostile conditions that expect new attempts and attacks. Thus, it is better to support reputation systems in that regard rather than other solutions that can be totally and entirely useless with the occurrence of new misbehavior strategies.

234 Wireless Sensor Networks – Technology and Protocols

nodes' behavior like that in WSN.

behavior, which are core concepts in reputation systems.

layer as a provision of secure routing in WSN is presented.

secure routing operation.

**1.1. Motivation** 

following reasons:

compromised nodes or insider attacks; i.e. nodes belong to the same network community. Among different approaches in solving this problem, reputation system based solution is one technique that has generated enough interest among WSN research community. Reputation systems attempt to provide security by allowing different nodes to rate each other based on their routing activities and behavior analysis. When a node has an experience profile about its neighbors, it may select the node that it trusts more, and, hence, achieve a

In this chapter, a reputation system solution for behavioral based attacks at the network

In this work, we provide a reputation system based solution for routing security in WSN. We believe that such a solution approach is a feasible and applicable solution for the

 Conventional security solution such as cryptography can successfully defend against outsiders' attack. The mechanics of such solutions fail when the attack is done by insiders or compromised nodes. Some of such attacks are intentionally performed like the misbehavior of selfish nodes and compromised nodes. Other attacks can be carriedout unintentionally by faulty nodes [2]. Thus, security systems like reputation based security solutions that have a mechanism to treat such attacks by behavior analysis are more suitable. This is especially true in networks where such misbehavior is very

possible or even it is the dominant type of attacks, which is the case in WSN.

 In contrast to different secure routing mechanisms, reputation based systems provide a means for an adaptive and dynamic decision making and reaction at the individual node level behavior. Such features are needed in networks that exhibit dynamicity in

 Most WSN deployments and applications invite a very dynamic networking nature. The current conditions and statistics of the network will change from time to time. The security system, thus, must accept to tune itself to these changes at the network level. WSN life and operation depends on the cooperation of nodes like any other ad hoc network. This implies that the security interest of a node is not only about itself but also about the whole network. As a result, such networks will prefer to communicate security information in order to keep the network healthy. This is an important feature of reputation systems. Node rating is one type of information that contributes to node's decision making and can be communicated as second hand information. However, the node reaction is also important and affects other nodes' decisions. Thus, the security system should have the feature of a consulted and well-analyzed decision-making and

 An interesting and important feature of any reputation system is that it follows a generalized and modular solution approach to fight against any attack in a general framework. The system then is customized to face a subset of these attacks. Thus, new In literature, there are different, proposed reputation based solutions for secure routing in ad hoc networks. Very familiar examples include CONFIDANT (Cooperation Of Nodes – Fairness In Dynamic Ad-hoc Networks) [3], SORI (Secure and Objective Reputation-Based Incentive Scheme for Ad Hoc Networks) [4] and CORE (Collaborative Reputation Mechanism to Enforce Node Cooperation in Mobile Ad Hoc Networks)[5]. There are also other solutions that are close to the reputation systems but they do not follow the general mechanism. Examples are watchdog and pathrater as well as context-aware detection [6, 7].

As these solutions are applied to ad hoc networks, the conclusion of applying them to wireless sensor network as a type of ad hoc networks is not totally accurate. There are several reasons that show the need to have a special reputation system design and implementation that targets WSN. This differentiation comes from the following facts:

