Xinyu Xing

Security Analysis and Authentication Improvement for IEEE 802.11i Specification

The IEEE 802.11i amendment has been finalized to address the security issues in wireless local area networks. A prodigious amount of research has demonstrated that the IEEE 802.11i specification is sufficient to prevent unauthorized access and use. In this paper, we analyze the IEEE 802.11i wireless networking amendment with respect to data confidentiality, integrity, mutual authentication and availability. Our analysis indicates that a number of serious threats have still not been addressed by the 802.11i amendment. This includes DoS attacks, insider attacks, offline guessing attacks, etc. Furthermore, configuring security features on a commercial Wi-Fi network is moderately-to-very difficult. Towards this end, this paper proposes an improved authentication mechanism which adopts asymmetric cryptography and thus accomplishes link-layer frame protection. Through our further analysis and discussion, we conclude that the proposed mechanism not only prevents potential security threats but also accomplishes autonomic security configuration without human intervention.

Mobile Agent for Efficient Routing among Source Nodes in Wireless Sensor Networks

In wireless sensor network, a lot of sensory traffic with redundancy is produced due to massive node density and their diverse placement. This causes the decline of scarce network resources such as bandwidth and energy, thus decreasing the lifetime of sensor network. Recently, mobile agent is proposed as a solution to overcome these problems. Mobile agent accounts for performing data processing and making data aggregation decisions at nodes rather than bring data back to a central processor (sink). Using this approach, redundant sensory data will be eliminated. However, carrying a huge amount of aggregated data among source nodes, using mobile agent, requires immensely planned routing. This is to avoid hastily burning source nodes energy in interest region. Towards this end, we propose a novel approach to achieve optimal routing path for mobile agent. Our proposed approach has two folds. Firstly, Dijkstras algorithm is used to generate a complete graph to connect all source nodes. Secondly, genetic algorithm is performed on a completed graph to generate best approximated route. To demonstrate the feasibility of our approach, formal analysis and experimental results are presented.

Fault reconnaissance agent for sensor networks

One of the key prerequisite for a scalable, effective and efficient sensor network is the utilization of low-cost, low-overhead and high-resilient fault-inference techniques. To this end, we propose an intelligent agent system with a problem solving capability to address the issue of fault inference in sensor network environments. The intelligent agent system is designed and implemented at base-station side. The core of the agent system - problem solver - implements a fault-detection inference engine which harnesses Expectation Maximization (EM) algorithm to estimate fault probabilities of sensor nodes. To validate the correctness and effectiveness of the intelligent agent system, a set of experiments in a wireless sensor testbed are conducted. The experimental results show that our intelligent agent system is able to precisely estimate the fault probability of sensor nodes.

Tracking Anonymous Sinks in Wireless Sensor Networks

Nowadays, wireless sensor networks are deployed in a wide range of applications such as military. To enable sinks to avoid physical attacks from adversaries, most of WSNs adopt sink-location privacy mechanisms. By utilizing these mechanisms, an adversary cannot analyze packet traffic and perform hop-by-hop trace-back, and thus deduce the location of a sink. In this paper, we propose an attack approach to track anonymous sinks. It utilizes a Pseudo-Noise (PN) code to mark a data flow in an invisible manner. An adversary is able to interfere with a source node’s traffic by embedding a secure signal into the node’s traffic. The signal is carried along with the traffic from the source node to the sink. Therefore, the attacker can recognize the location of a sink node by tracking the invisible secure signal. Through our simulation experiments, we conclude that the proposed attack approach is able to track an anonymous sink without additional traffic overhead.

Agent-based routing for wireless sensor network

In environments where node density is massive, placement is heterogeneous and lot of sensory traffic with redundancy is produced; waste of resources such as bandwidth and energy occurs. This waste of resources minimize the network life time. Numerous routing schemes have been proposed to address such problems. They all tend to focus on similar direction, i.e. to find minimum energy path to increase the life time of the network. In this paper, we argue that it is not always wise to use the minimum energy path. Nodes along the optimal path will be used rapidly, burn out energy aggressively and eventually die hastily creating communication holes in network. This brings rapid change in the topology resulting in increased latency, poor connectivity and production of heterogeneous subnets. Therefore, utilizing suboptimal paths is encouraged for load balancing among sensor nodes. We unmitigated our efforts to augment the node life time in sensor network by frequent use of suboptimal paths, and reducing redundant sensory network traffic. Towards this end, we propose an agent-based routing approach that incorporates static and mobile agents. Static agent is responsible for calculating and maintaining the set of optimal paths. Mobile agent accounts for performing data processing and making data aggregation decisions at nodes in the network rather than bring data back to a central processor (sink). To demonstrate the performance evaluation, a prototype of a simulator is implemented.

An intelligent agent for fault reconnaissance in sensor networks

An embedded sensor network is a system of nodes, each of which is equipped with a certain amount of sensing, actuating, computation, communication and storage components. Two major components of sensor nodes are sensing unit and wireless transceiver. They directly interact with nodes in wireless sensor networks (WSNs) that are easily prone to failure due to hardware failure, communication link errors, energy depletion, malicious attacks, etc. Even if the sensor node hardware is in excellent condition, still the communication between sensor nodes depends on many factors such as signal strength, obstacles and interference. Degradation in these factors results in low reliability of sensor nodes. One of the key prerequisite for an effective, efficient embedded sensor network is utilization of low-cost, low-overhead and high-resilient fault-inference techniques. Our attempt is to address fault-inference issues in sensor networks using an agent-based approach. Our proposed approach involves an intelligent agent that outfitted with a fault-inference engine. This engine profits from Expectation Maximization (EM) algorithm to evaluate fault probabilities of sensor nodes. Our experiment in a wireless sensor testbed is conducted to demonstrate the correctness and effectiveness of our approach.

Agent based approach towards energy aware routing in wireless sensor networks

In an environment where node density is massive, placement is heterogeneous and lots of sensory traffic with redundancy is produced; individual nodes waste limited wireless bandwidth and consume lot of energy. This minimizes their life time on the network. To handle such problem number of routing schemes have been proposed by researchers. These schemes tend to find the minimum energy path to prolong the network life. In this paper, we argue that it is not always wise to use the minimum energy path. Nodes along the optimal path will be used rapidly, burn out energy aggressively and eventually die hastily creating communication holes in network. This brings rapid change in the topology resulting in increased latency, poor connectivity and production of heterogeneous subnets. Thus, it is better to occasionally use suboptimal paths. We unmitigated our efforts to augment the node life time in sensor network by frequent use of suboptimal paths, and reducing redundant sensory network traffic. Towards this end, we propose an agent- based directed diffusion approach that incorporates static and mobile agents. Static agent is responsible for calculating and maintaining the set of optimal paths. Mobile agent main function is to perform data processing and make data aggregation decisions at nodes in the network rather than bring data back to a central processor (sink). This paper provides an analytical model for data dissemination for both approaches. To demonstrate the performance evaluation, a prototype of a simulator is implemented.