Trust Management in Mobile Ad Hoc Networks for QoS Enhancing

In a collaborative environment such as MANET, nodes reliability evaluation is vital. Trust Management can be used to ensure such healthy collaboration it offers a formal and unified framework for trust specification and interpretation. Establishing trustworthy relationships is generally done by maintaining a reputation for each node computed based on direct observations or neighbors' observations exchanged using recommendations. Unfortunately, for malicious reason, such method may be faked by cheaters: several nodes collude in order to rate each other with the maximum value and decrease other nodes' reputations by giving negative recommendations. The main contribution of this chapter is then, the proposition of a trust based environment for MANET and securing it against collusion attack in order to enhance the network QoS. This is achieved using three steps: (1) the definition of a formal trust based environment (2) the addition of a process handling collusion attack and (3) the extension of the whole proposition by a delegation process allowing nodes functionalities sharing.