Dealing with Collusion Attack in a Trust-Based MANET

Trust allows collaborating entities to cope with their uncertainty especially when these collaborations are the bedrock of the network existence such as in Mobile Ad hoc NETworks (MANET). The trustworthiness of collaborators can be evaluated using reputations. Reputation is an appreciation of the node credibility created through past actions. It can be calculated using direct observations and/or using other nodes appreciations exchanged through recommendations. Unfortunately, some nodes may be attempted to disturb the network by sending faked recommendations in order to decrease the reputation of a benevolent node or to increase the one of an attacker. That's collusion attack. The main contribution of this paper concerns then, the proposition of collusion prevention and detection process in a trust based MANET.