No abstract

Distributed denial of service (DoS) attacks on cyber-resources are complex problems that are difficult to completely define, characterize, and mitigate. We recognize the process-nature of DoS attacks and view them from multiple perspectives. Identification of opportunities for mitigation and further research may result from this attempt to characterize the DoS problem space. We examine DoS attacks from the point of view of 1) a high-level that establishes common terminology and a framework for discussing the DoS process, 2) layers of the communication stack, from attack origination to the victim of the attack, 3) specific network and computer elements, and 4) attack manifestations. We also examine DoS issues associated with wireless communications. Using this collection of views, one begins to see the DoS problem in a holistic way that may lead to improved understanding, new mitigation strategies, and fruitful research.

In this paper, we discuss several specific threats directed at the routing data of an ad hoc network. We address security issues that arise from wrapping authentication mechanisms around ad hoc routing data. We show that this bolt-on approach to security may make certain attacks more difficult, but still leaves the network routing data vulnerable. We also show that under a certain adversarial model, most existing routing protocols cannot be secured with the aid of digital signatures. 4This page intentionally left blank.5

Mobile wireless ad hoc networks that are resistant to adversarial manipulation are necessary for distributed systems used in military and security applications. Critical to the successful operation of these networks, which operate in the presence of adversarial stressors, are robust and efficient information assurance methods. In this report we describe necessary enhancements for a distributed certificate authority (CA) used in secure wireless network architectures. Necessary cryptographic algorithms used in distributed CAs are described and implementation enhancements of these algorithms in mobile wireless ad hoc networks are developed. The enhancements support a network's ability to detect compromised nodes and facilitate distributed CA services. We provide insights to the impacts the enhancements will have on network performance with timing diagrams and preliminary network simulation studies. 4This page intentionally left blank.5

In high consequence systems, all layers of the protocol stack need security features. If network and data-link layer control messages are not secured, a network may be open to adversarial manipulation. The open nature of the wireless channel makes mobile wireless mobile ad hoc networks (MANETs) especially vulnerable to control plane manipulation. The objective of this research is to investigate MANET performance issues when cryptographic processing delays are applied at the data-link layer. The results of analysis are combined with modeling and simulation experiments to show that network performance in MANETs is highly sensitive to the cryptographic overhead. 4This page intentionally left blank.5