Soo Young Moon

Energy efficient filtering method in sensor networks

Wireless sensor networks (WSN) sense and report interesting events in the sensor field to users. Usually, the sensor field for WSN is hostile and lacks infrastructure, so WSNs are exposed to security threats. In false report injection attacks, attackers inject false reports into the network through compromised nodes. Among many countermeasures to the attacks, the statistical en-route filtering scheme (SEF) detects and drops false reports by collaborative generation and verification of event reports by sensor nodes. In SEF, each node verifies received reports based on a pre-determined probability without consideration of sending nodes, consuming unnecessary energy for report verification. In this paper, we propose an energy-efficient filtering method for sensor networks. In the method, each node controls its verification probabilities for event reports, which depend on sending nodes. The number of recent valid reports and the false traffic ratio of each neighbor node are used to determine the verification probability for each node. We confirmed that our method uses energy efficiently without weakening en-route filtering capability.

An energy-efficient routing method with intrusion detection and prevention for wireless sensor networks

Because of the features such as limited resources, wireless communication and harsh environments, wireless sensor networks (WSNs) are prone to various security attacks. Therefore, we need intrusion detection and prevention methods in WSNs. When the two types of schemes are applied, heavy communication overhead and resulting excessive energy consumption of nodes occur. For this reason, we propose an energy efficient routing method in an environment where both intrusion detection and prevention schemes are used in WSNs. We confirmed through experiments that the proposed scheme reduces the communication overhead and energy consumption compared to existing schemes.

Hybrid System Model Simulation Framework for Cyber-Physical Systems

Most of existing frameworks for modeling and simulation of hybrid systems represent continuous behavior of systems using ordinary differential equations (ODEs). ODE models can be represented as discrete event system specification (DEVS) models through discretization and simulated in the DEVS simulation framework. However, in cyber-physical systems (CPS), it is difficult to represent the continuous behavior of a system using an ODE because it can have unknown, unpredictable variables. In that case, it is needed to predict the model’s next event time by inference to embed the model in a DEVS model. We propose the simulation framework in which a fuzzy inference module is added to each simulation model to determine its next event time. The proposed method enables simulation of hybrid system models which can or cannot be represented using an ODE.

A Routing Path Construction Method for Key Dissemination Messages in Sensor Networks

Authentication is an important security mechanism for detecting forged messages in a sensor network. Each cluster head (CH) in dynamic key distribution schemes forwards a key dissemination message that contains encrypted authentication keys within its cluster to next-hop nodes for the purpose of authentication. The forwarding path of the key dissemination message strongly affects the number of nodes to which the authentication keys in the message are actually distributed. We propose a routing method for the key dissemination messages to increase the number of nodes that obtain the authentication keys. In the proposed method, each node selects next-hop nodes to which the key dissemination message will be forwarded based on secret key indexes, the distance to the sink node, and the energy consumption of its neighbor nodes. The experimental results show that the proposed method can increase by 50–70% the number of nodes to which authentication keys in each cluster are distributed compared to geographic and energy-aware routing (GEAR). In addition, the proposed method can detect false reports earlier by using the distributed authentication keys, and it consumes less energy than GEAR when the false traffic ratio (FTR) is ≥10%.

Energy Efficient Filtering Nodes Assignment Method for Sensor Networks Using Fuzzy Logic

Wireless Sensor Network (WSN) can enable context-aware services through sensing, processing, and reporting event information. Due to limited resources WSNs are vulnerable to various malicious attacks. In one of these attacks false event reports are generated to compromise the integrity of the sensor data. In most filtering schemes every sensor node on a path from an event source to a sink node operates as a filtering node which verifies received reports and determine whether they are valid or false. Hence, even the valid reports are verified multiple times as they are forwarded toward the sink node, causing unnecessary energy consumption. In this paper we propose a filtering nodes assignment method to reduce the energy consumption while verifying the event reports. The proposed method partitions the network into several areas and assigns filtering nodes for each area according to a fuzzy output value derived from the three inputs - the number of valid event reports received from the area, the elapsed time since the last valid event report received from the area, and the average hop count from the nodes in the area to the sink node. The experimental results show that the proposed method conserves sensor nodes’ energy and increases the network lifetime with similar security level.

A Method to Improve Energy Efficiency Using a Function that Evaluate the Probability of Attempts to Verify a Report at Intermediate Node in USN

Wireless sensor nodes operate in open environments. The deployed sensor nodes are very vulnerable to physical attacks from outside. Attackers compromise some sensor nodes. The compromised nodes by attackers can lead to false data injection into sensor networks. These attacks deplete the limited energy of sensor nodes. Ye et al. proposed the Statistical En-Route Filtering (SEF) as a countermeasure of the attacks. The sensor node in SEF examines the event reports based on certain uniform probability. Thus, the same energies are consumed in both legitimate reports and false reports. In this paper, we propose a method that each node controls the probability of attempts to verify a report to reduce energy consumption of sensor nodes. The probability is determined in consideration of the remaining energy of the node, the number of hops from the node to SINK node, the ratio of false reports. the proposed method can have security which is similar with SEF and consumes lower energy than SEF.

Adaptive False Data Filtering Method for Sensor Networks Based on Fuzzy Logic and Commutative Cipher

Wireless sensor networks are vulnerable to false data injection attacks in which attackers inject false reports into the networks through compromised nodes with the goal of deceiving sinks or depleting the resources of the relaying nodes. This paper presents an adaptive false data filtering method, which is based on the commutative cipher-based probabilistic filtering scheme. A security parameter, which determines the required number of participating nodes in each report generation, is controlled by a fuzzy rule-based system with the consideration of the factors that reflect the network status. The proposed method can be more energy-efficient than the base scheme in both legitimate and false traffic. The effectiveness of the proposed method is shown at the end of the paper with simulation results.

Key Management Scheme for Query Based Routing in Sensor Networks

Wireless sensor networks (WSN) are emerging technologies that enable various applications including tracking, monitoring and control. Because of ad-hoc, wireless communication and limitation of resources, much vulnerability arises. In false report injection attacks, an attacker tries to confuse a user or deplete energy resource of sensor nodes by injecting false reports through compromised nodes. One of countermeasures to the attacks is the commutative cipher based en-route filtering (CCEF). In CCEF, if a cluster header (CH) is compromised, false reports injected through it always reach the base station (BS).To solve the problem, we propose the key management scheme for query based routing in sensor networks. In the proposed scheme, a CH can not derive the session key without help of its neighbor nodes and let false reports reach the BS. We confirmed the effectiveness of the proposed scheme in terms of en-route filtering capability.