Many emerging mobile networks aim to provide wireless network services without relying on any infrastructure. The main challenge in these networks comes from their self-organized and distributed nature. There is an inherent reliance on collaboration among the participants in order to achieve the aimed functionalities. Therefore, establishing and quantifying trust, which is the driving force for collaboration, is important for applications in mobile networks. This dissertation focuses on evaluating and quantifying trust to stimulate collaboration in mobile networks, introducing uncertainty concepts and metrics, as well as providing the various analysis and applications of uncertainty-aware reputation systems. Many existing reputation systems sharply divide the trust value into right or wrong, thus ignoring another core dimension of trust: uncertainty. As uncertainty deeply impacts a node's anticipation of others' behavior and decisions during interaction, we include it in the reputation system. Specifically, we use an uncertainty metric to directly reflect a node's confidence in the sufficiency of its past experience, and study how the collection of trust information may affect uncertainty in nodes' opinions. Higher uncertainty leads to higher transaction cost and reduced acceptance of communication. We exploit mobility to efficiently reduce uncertainty and to speed up trust convergence. We also apply the new reputation system to enhance the analysis of the interactions among mobile nodes, and present three sample uncertainty-aware applications. We integrate the uncertainty-aware reputation model with game theory tools, and enhance the analysis on interactions among mobile nodes. / Instead of reactively protecting the mobile networks from existing attacks as in the traditional security paradigms, the analysis in this dissertation gives more insights on nodes' rationality in the interaction, which will enable the mechanism design in mobile networks to be security and incentive compatible. Moreover, we present three sample applications, in which we clearly identify the challenges, specifically formalize the problems, and cleverly employ the uncertainty mitigation schemes. These applications show that the uncertainty definition and mitigation schemes can benefit a broad range of applications, including fields such as security, network services, and routing. / by Feng Li. / Vita. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

The IP Multimedia Subsystem (IMS) has gone from just a step in the evolution of the GSM cellular architecture control core, to being the de-facto framework for Next Generation Network (NGN) implementations and deployments by operators world-wide, not only cellular mobile communications operators, but also fixed line, cable television, and alternative operators. With this transition from standards documents to the real world, engineers in these new multimedia communications companies need to face the task of making these new networks secure against threats and real attacks that were not a part of the previous generation of networks. We present the IMS and other competing frameworks, we analyze the security issues, we present the topic of Security Patterns, we introduce several new patterns, including the basis for a Generic Network pattern, and we apply these concepts to designing a security architecture for a fictitious 3G operator using IMS for the control core. / by Jose M. Ortiz-Villajos. / Thesis (M.S.C.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

This research addresses communication security in the highly constrained wireless sensor environment. The goal of the research is twofold: (1) to develop a key management scheme that provides these constrained systems with the basic security requirements and evaluate its effectiveness in terms of scalability, efficiency, resiliency, connectivity, and flexibility, and (2) to implement this scheme on an appropriate routing platform and measure its efficiency. / The proposed key management scheme is called Hierarchical Key Establishment Scheme (HIKES). In HIKES, the base station, acting as the central trust authority, empowers randomly selected sensors to act as local trust authorities, authenticating on its behalf the cluster members and issuing to them all secret keys necessary to secure their communications. HIKES uses a novel key escrow scheme that enables any sensor node selected as a cluster head to generate all the cryptographic keys needed to authenticate other sensors within its cluster. This scheme localizes secret key issuance and reduces the communication cost with the base station. The key escrow scheme also provides the HIKES with as large an addressing mechanism as needed. HIKES also provides a one-step broadcast authentication mechanism. HIKES provides entity authentication to every sensor in the network and is robust against most known attacks. We propose a hierarchical routing mechanism called Secure Hierarchical Energy-Efficient Routing protocol (SHEER). SHEER implements HIKES, which provides the communication security from the inception of the network. SHEER uses a probabilistic broadcast mechanism and a three-level hierarchical clustering architecture to improve the network energy performance and increase its lifetime. / Simulation results have shown that HIKES provides an energy-efficient and scalable solution to the key management problem. Cost analysis shows that HIKES is computationally efficient and has low storage requirement. Furthermore, high degree of address flexibility can be achieved in HIKES. Therefore, this scheme meets the desired criteria set forth in this work. Simulation studies also show that SHEER is more energy-efficient and has better scalability than the secure version of LEACH using HIKES. / by Jamil Ibriq. / Thesis (Ph. D.)--Florida Atlantic University, 2007. / Includes bibliography. / Also available in print. / Electronic reproduction. Boca Raton, FL : 2007. Mode of access: World Wide Web.

Ka-Lung Chong. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 80-83). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.iii / Chapter 1 --- Introduction & Motivation --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Internet Commerce --- p.3 / Chapter 1.3 --- Motivation --- p.6 / Chapter 1.4 --- Related Work --- p.7 / Chapter 1.4.1 --- Cryptographic Techniques --- p.7 / Chapter 1.4.2 --- Internet Payment Systems --- p.9 / Chapter 1.5 --- Contribution --- p.16 / Chapter 1.6 --- Outline of the Thesis --- p.17 / Chapter 2 --- A New Payment Model --- p.19 / Chapter 2.1 --- Model Description --- p.19 / Chapter 2.2 --- Characteristics of Our Model --- p.22 / Chapter 2.3 --- Model Architecture --- p.24 / Chapter 2.4 --- Comparison --- p.30 / Chapter 2.5 --- System Implementation --- p.30 / Chapter 2.5.1 --- Acquirer Interface --- p.31 / Chapter 2.5.2 --- Issuer Interface --- p.32 / Chapter 2.5.3 --- Merchant Interface --- p.32 / Chapter 2.5.4 --- Payment Gateway Interface --- p.33 / Chapter 2.5.5 --- Payment Cancellation Interface --- p.33 / Chapter 3 --- A E-Commerce Application - TravelNet --- p.35 / Chapter 3.1 --- System Architecture --- p.35 / Chapter 3.2 --- System Features --- p.38 / Chapter 3.3 --- System Snapshots --- p.39 / Chapter 4 --- Simulation --- p.44 / Chapter 4.1 --- Objective --- p.44 / Chapter 4.2 --- Simulation Flow --- p.45 / Chapter 4.3 --- Assumptions --- p.49 / Chapter 4.4 --- Simulation of Payment Systems --- p.50 / Chapter 5 --- Discussion of Security Concerns --- p.54 / Chapter 5.1 --- Threats to Internet Payment --- p.54 / Chapter 5.1.1 --- Eavesdropping --- p.55 / Chapter 5.1.2 --- Masquerading --- p.55 / Chapter 5.1.3 --- Message Tampering --- p.56 / Chapter 5.1.4 --- Replaying --- p.56 / Chapter 5.2 --- Aspects of A Secure Internet Payment System --- p.57 / Chapter 5.2.1 --- Authentication --- p.57 / Chapter 5.2.2 --- Confidentiality --- p.57 / Chapter 5.2.3 --- Integrity --- p.58 / Chapter 5.2.4 --- Non-Repudiation --- p.58 / Chapter 5.3 --- Our System Security --- p.58 / Chapter 5.4 --- TravelNet Application Security --- p.61 / Chapter 6 --- Discussion of Performance Evaluation --- p.64 / Chapter 6.1 --- Performance Concerns --- p.64 / Chapter 6.2 --- Experiments Conducted --- p.65 / Chapter 6.2.1 --- Description --- p.65 / Chapter 6.2.2 --- Analysis on the Results --- p.65 / Chapter 6.3 --- Simulation Analysis --- p.69 / Chapter 7 --- Conclusion & Future Work --- p.72 / Chapter A --- Experiment Specification --- p.74 / Chapter A.1 --- Configuration --- p.74 / Chapter A.2 --- Experiment Results --- p.74 / Chapter B --- Simulation Specification --- p.77 / Chapter B.1 --- Parameter Listing --- p.77 / Chapter B.2 --- Simulation Results --- p.77 / Bibliography --- p.80

The discipline of information security management is still in its infancy as evidenced by the lack of empirical scholarly work in this area. Most research within the information security domain focuses on specific technologies and algorithms and how it impacts the principles of confidentiality, integrity, and availability. But, an important area receiving little attention is the antecedents of effective information security management at the organizational level (Stanton, Guzman, Stam & Caldera, 2003). The little empirical research that has been conducted in this area has shown that information security management in many organizations is poor (Baskerville, 1993; Shimeall & McDermott, 1999). Several researchers have identified the need for methods to measure the organization-wide information security posture of organizations (Eloff & Von Solms, 2000; James, 1996). This dissertation attempts to measure the organization-wide information security posture by examining benchmark variables that assess role, planning orientation, and performance structure within the organization. Through this conceptualization of an organization's information security posture, a means is presented to measure overall information security and how it impacts the effective utilization of information security strategies. The presence of the dependent variable, effectiveness, gives academics and practitioners a success measure which can guide more effective decision making in the information security domain. An additional aim of this dissertation is to empirically examine the influence of management practices and decisions on effective use of information security strategies within the organization. The issues of centralization versus decentralization of information security activities will be evaluated along with its impact on information security posture of organizations and the effectiveness of the organization's information security strategies. Data was collected from 119 IT and information security executives. Results show that how the organization structures information security activities is not correlated with more effective utilization of information security strategies. Meanwhile, the organization's information security posture is significantly correlated with more effective utilization of information security strategies. The implications of this research is discussed.

The primary objective of the proposed research is to develop a framework for smart and robust fingerprinting of networked systems. Many fingerprinting techniques have been proposed in the past, however most of these techniques are designed for a specific purpose, such as Operating System (OS) fingerprinting, Access Point (AP) fingerprinting, etc. Such standalone techniques often have limitations which render them dysfunctional in certain scenarios or against certain counter measures. In order to overcome such limitations, we propose a fingerprinting framework that can combine multiple fingerprinting techniques in a smart manner, using a centralized decision making engine. We believe that any given scenario or a counter measure is less likely to circumvent a group of diverse fingerprinting techniques, which serves as the primary motivation behind the aforementioned method of attack. Another major portion of the thesis concentrates on the design and development of a device and device type fingerprinting sub-module (GTID) that has been integrated into the proposed framework. This sub-module used statistical analysis of packet inter arrival times (IATs) to identify the type of device that is generating the traffic. This work also analyzes the performance of the identification technique on a real campus network and propose modifications that use pattern recognition neural networks to improve the overall performance. Additionally, we impart capabilities to the fingerprinting technique to enable the identification of 'Unknown' devices (i.e., devices for which no signature is stored), and also show that it can be extended to perform both device and device type identification.

With the fast development of wireless networks and devices, Mobile IP is expected to be used widely so that mobile users can access the Internet anywhere, anytime without interruption. However, some problems, such as firewall traversal and use of private IP addresses, restrict use of Mobile IP. The objective of this thesis is to design original schemes that can enable a mobile node at abroad to access its home network as well as the Internet securely and that can help Mobile IP to be used widely and commercially. Our solutions are secure, efficient, and scalable. They can be implemented and maintained easily. In this thesis, we mainly consider Mobile IPv4, instead of Mobile IPv6. Three research topics are discussed. In each topic, the challenges are investigated and the new solutions are presented. The first research topic solves the firewall traversal problems in Mobile IP. A mobile node cannot access its firewall-protected home network if it fails the authentication by the firewall. We propose that an IPsec tunnel be established between the firewall and the foreign agent for firewall traversal and that an IPsec transport security association be shared by the mobile node and a correspondent node for end-to-end security. The second topic researches further on firewall traversal problems and investigates the way of establishing security associations among network entities. A new security model and a new key distribution method are developed. With the help of the security model and keys, the firewall and the relevant network entities set up IPsec security associations to achieve firewall traversal. A mobile node from a private home network cannot communicate with other hosts with its private home address when it is visiting a public foreign network. A novel and useful solution is presented in the third research topic. We suggest that the mobile node use its Network Access Identifier (NAI) as its identification and obtain a public home address from its home agent. In addition, a new tunnel between the mobile node and its home agent is proposed.

In this dissertation, we propose RADAR - compileR and micro-Architecture supported intrusion prevention, Detection, Analysis and Recovery. RADAR is an infrastructure to help prevent, detect and even recover from attacks to critical software. Our approach emphasizes collaborations between compiler and micro-architecture to avoid the problems of purely software or hardware based approaches. With hardware support for cryptographic operations, our infrastructure can achieve strong process isolation to prevent attacks from other processes and to prevent certain types of hardware attacks. Moreover, we show that an unprotected system address bus leaks critical control flow information of the protected software but has never been carefully addressed previously. To enhance intrusion prevention capability of our infrastructure further, we present a scheme with both innovative hardware modification and extensive compiler support to eliminate most of the information leakage on system address bus. However, no security system is able to prevent all attacks. In general, we have to assume that certain attacks will get through our intrusion prevention mechanisms. To protect software from those attacks, we build a second line of defense consisted of intrusion detection and intrusion recovery mechanisms. Our intrusion detection mechanisms are based on anomaly detection. In this dissertation, we propose three anomaly detection schemes. We demonstrate the effectiveness of our anomaly detection schemes thus the great potential of what compiler and micro-architecture can do for software security. The ability to recover from an attack is very important for systems providing critical services. Thus, intrusion recoverability is an important goal of our infrastructure. We focus on recovery of memory state in this dissertation, since most attacks break into a system by memory tampering. We propose two schemes for intrusion analysis. The execution logging based scheme incurs little performance overhead but has higher demand for storage and memory bandwidth. The external input points tagging based scheme is much more space and memory bandwidth efficient, but leads to significant performance degradation. After intrusion analysis is done and tampered memory state is identified, tampered memory state can be easily recovered through memory updates logging or memory state checkpointing.

We consider the problem of designing enterprise network security systems which are easy to manage, robust and flexible. This problem is challenging. Today, most approaches rely on host security, middleboxes, and complex interactions between many protocols. To solve this problem, we explore how new programmable networking paradigms can facilitate fine-grained network control. We present Resonance, a system for securing enterprise networks , where the network elements themselves en- force dynamic access control policies through state changes based on both flow-level information and real-time alerts. Resonance uses programmable switches to manipulate traffic at lower layers; these switches take actions (e.g., dropping or redirecting traffic) to enforce high-level security policies based on input from both higher-level security boxes and distributed monitoring and inference systems. Using our approach, administrators can create security applications by first identifying a state machine to represent different policy changes and then, translating these states into actual network policies. Earlier approaches in this direction (e.g., Ethane, Sane) have remained low-level requiring policies to be written in languages which are too detailed and are difficult for regular users and administrators to comprehend. As a result, significant effort is needed to package policies, events and network devices into a high-level application. Resonance abstracts out all the details through its state-machine based policy specification framework and presents security functions which are close to the end system and hence, more tractable. To demonstrate how well Resonance can be applied to existing systems, we consider two use cases. First relates to "Network Admission Control" problem. Georgia Tech dormitories currently use a system called START (Scanning Technology for Automated Registration, Repair, and Response Tasks) to authenticate and secure new hosts entering the network [23]. START uses a VLAN-based approach to isolate new hosts from authenticated hosts, along with a series of network device interactions. VLANs are notoriously difficult to use, requiring much hand-holding and manual configuration. Our interactions with the dorm network administrators have revealed that this existing system is not only difficult to manage and scale but also inflexible, allowing only coarse-grained access control. We implemented START by expressing its functions in the Resonance framework. The current system is deployed across three buildings in Georgia Tech with both wired as well as wireless connectivities. We present an evaluation of our system's scalability and performance. We consider dynamic rate limiting as the second use case for Resonance. We show how a network policy that relies on rate limiting and traffic shaping can easily be implemented using only a few state transitions. We plan to expand our deployment to more users and buildings and support more complex policies as an extension to our ongoing work. Main contributions of this thesis include design and implementation of a flexible access control model, evaluation studies of our system's scalability and performance, and a campus-wide testbed setup with a working version of Resonance running. Our preliminary evaluations suggest that Resonance is scalable and can be potentially deployed in production networks. Our work can provide a good platform for more advanced and powerful security techniques for enterprise networks.

The objective of this research is to investigate improved methods for distributing certificate revocation lists (CRLs) in vehicular ad hoc networks (VANETs). VANETs are a subset of mobile ad hoc networks composed of network-equipped vehicles and infrastructure points, which will allow vehicles to communicate with other vehicles and with roadside infrastructure points. While sharing some of the same limitations of mobile ad hoc networks, such as lack of infrastructure and limited communications range, VANETs have several dissimilarities that make them a much different research area. The main differences include the size of the network, the speed of the vehicles, and the network security concerns. Confidentiality, authenticity, integrity, and availability are some of the standard goals of network security. While confidentiality and authenticity at times seem in opposition to each other, VANET researchers have developed many methods for enhancing confidentiality while at the same time providing authenticity. The method agreed upon for confidentiality and authenticity by most researchers and the IEEE 1609 working group is a public key infrastructure (PKI) system. An important part of any PKI system is the revocation of certificates. The revocation process, as well as the distribution of revocation information, is an open research problem for VANETs. This research develops new methods of CRL distribution and compares them to existing methods proposed by other researchers. The new methods show improved performance in various vehicle traffic densities.