A Mobile Ad hoc Network (MANET) consists of a set of communicating wireless mobile nodes or devices that do not have any form of fixed infrastructure or centralized authority. The security in MANET has become a significant and active topic within the research community. This is because of high demand in sharing streaming video and audio in various applications, one MANET could be setup quickly to facilitate communications in a hostile environment such as battlefield or emergency situation likes disaster rescue operation. In spite of the several attacks aimed at specific nodes in MANET that have been uncovered, some attacks involving multiple nodes still receive little attention. A reason behind this is because people make use of security mechanisms applicable to wired networks in MANET and overlook the security measures that apply to MANET. Furthermore, it may also have to do with the fact that no survey or taxonomy has been done to clarify the characteristics of different multiple node attacks. This thesis addresses the aforementioned gap by providing a proper definition and categorization of collaborative attacks against MANET from the various multiple node attacks found. Simulation using OPNET Modeler was used to investigate the performance impact of a collaborative blackhole attack on a mobile ad hoc network. Network throughput, packet delivery ratio and end-to-end delay are the performance metrics used in our result analysis. Based on the analyses of performance metrics made, we realised the consequences of a collaborative blackhole attack on MANET. In order to prevent or reduce these consequences, we also discuss a number of mitigation plans to counteract the different kinds of collaborative attacks. Keywords: MANET, Collaborative Attacks, Multiple Node, Blackhole. / Contact Information: Author(s): Cong Hoan Vu Address: Folkparksvägen 19:08, 372 40 Ronneby, Sweden. E-mail: vuconghoan@gmail.com Adeyinka Soneye Address: Polhemsgatan 27B, LGH 30, 371 40 Karlskrona, Sweden. E-mail: adso07@student.bth.se

abstract: An integrated methodology combining redundant clock tree synthesis and pulse clocked latches mitigates both single event upsets (SEU) and single event transients (SET) with reduced power consumption. This methodology helps to change the hardness of the design on the fly. This approach, with minimal additional overhead circuitry, has the ability to work in three different modes of operation depending on the speed, hardness and power consumption required by design. This was designed on 90nm low-standby power (LSP) process and utilized commercial CAD tools for testing. Spatial separation of critical nodes in the physical design of this approach mitigates multi-node charge collection (MNCC) upsets. An advanced encryption system implemented with the proposed design, compared to a previous design with non-redundant clock trees and local delay generation. The proposed approach reduces energy per operation up to 18% over an improved version of the prior approach, with negligible area impact. It can save up to 2/3rd of the power consumption and reach maximum possible frequency, when used in non-redundant mode of operation. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2015