A Scalable Trust Management scheme for Mobile Ad Hoc Networks

Mobile ad hoc networks MANETs, have special resource requirements and different topology features, they establish themselves on fly without reliance on centralized or specialized entities such as base stations. All the nodes must cooperate with each other in order to send packets, forwarding packets, responding to routing messages, sending recommendations, among others, Cooperating nodes must trust each other. In MANETs, an untrustworthy node can wreak considerable damage and adversely affect the quality and reliability of data. Therefore, analyzing the trust level of a node has a positive influence on the confidence with which an entity conducts transactions with that node. This thesis presents a new trust management scheme to assign trust levels for spaces or nodes in ad hoc networks. The scheme emulates the human model which depends on the previous individual experience and on the intercession or recommendation of other spaces in the same radio range. The trust level considers the recommendation of trustworthy neighbors and their own experience. For the recommendation computation, we take into account not only the trust level, but also its accuracy and the relationship maturity. The relationship rationality -maturity-, allows nodes to improve the efficiency of the proposed model for mobile scenarios. We also introduce the Contribution Exchange Protocol (CEP) which allows nodes to exchange Intercessions and recommendation about their neighbors without disseminating the trust information over the entire network. Instead, nodes only need to keep and exchange trust information about nodes within the radio range. Without the need for a global trust knowledge. Different from most related works, this scheme improves scalability by restricting nodes to keep and exchange trust information solely with direct neighbors, that is, neighbors within the radio range. We have developed a simulator, which is specifically designed for this model, in order to evaluate and identify the main characteristics of the proposed system. Simulation results show the correctness of this model in a single-hop network. Extending the analysis to mobile multihop networks, shows the benefits of the maturity relationship concept, i.e. for how long nodes know each other, the maturity parameter can decrease the trust level error up to 50%. The results show the effectiveness of the system and the influence of main parameters in the presence of mobility. At last, we analyze the performance of the CEP protocol and show its scalability. We show that this implementation of CEP can significantly reduce the number messages

A Novel Cooperative Intrusion Detection System for Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) have experienced rapid growth in their use for various military, medical, and commercial scenarios. This is due to their dynamic nature that enables the deployment of such networks, in any target environment, without the need for a pre-existing infrastructure. On the other hand, the unique characteristics of MANETs, such as the lack of central networking points, limited wireless range, and constrained resources, have made the quest for securing such networks a challenging task. A large number of studies have focused on intrusion detection systems (IDSs) as a solid line of defense against various attacks targeting the vulnerable nature of MANETs. Since cooperation between nodes is mandatory to detect complex attacks in real time, various solutions have been proposed to provide cooperative IDSs (CIDSs) in efforts to improve detection efficiency. However, all of these solutions suffer from high rates of false alarms, and they violate the constrained-bandwidth nature of MANETs. To overcome these two problems, this research presented a novel CIDS utilizing the concept of social communities and the Dempster-Shafer theory (DST) of evidence. The concept of social communities was intended to establish reliable cooperative detection reporting while consuming minimal bandwidth. On the other hand, DST targeted decreasing false accusations through honoring partial/lack of evidence obtained solely from reliable sources. Experimental evaluation of the proposed CIDS resulted in consistently high detection rates, low false alarms rates, and low bandwidth consumption. The results of this research demonstrated the viability of applying the social communities concept combined with DST in achieving high detection accuracy and minimized bandwidth consumption throughout the detection process