Lynda Mokdad

Detection of Radio Interference Attacks in VANET

Due to their nature, Vehicular Ad hoc NETwork (VANET) is vulnerable to Denial of Service (DoS) attacks, such as jamming attack. The objective of a jammer is to interfere with legitimate wireless communications, and to degrade the overall QoS of the network. In this paper, we propose a model to detect a particular class of Jamming attack, in which the jammer transmits only when valid radio activity is signaled from its radio hardware. This detection model is based upon the measurement of error distribution.

Enhancing data security in ad hoc networks based on multipath routing

An ad hoc network is a self-organizing network of wireless links connecting mobile nodes. The mobile nodes can communicate without an infrastructure. They form an arbitrary topology, where the nodes play the role of routers and are free to move randomly. Ad hoc networks proved their efficiency being used in different fields but they are highly vulnerable to security attacks and dealing with this is one of the main challenges of these networks today. Recently, some solutions are proposed to provide authentication, confidentiality, availability, secure routing and intrusion detection in ad hoc networks. Implementing security in such dynamically changing networks is a hard task. Ad hoc network characteristics should be taken into consideration to be able to design efficient solutions. In this study, we focus on improving the flow transmission confidentiality in ad hoc networks based on multipath routing. Indeed, we take advantage of the existence of multiple paths between nodes in an ad hoc network to increase the confidentiality robustness of transmitted data. In our approach the original message to secure is split into shares that are encrypted and combined then transmitted along different disjointed existing paths between sender and receiver. Even if an attacker succeeds to obtain one or more transmitted shares, the probability that the original message will be reconstituted is very low. We compare our approach with existing ad hoc multipath security solutions and present performance evaluations of our protocol SDMP (Securing Data based Multipath Routing).

Performance evaluation tools for QoS MAC protocol for wireless sensor networks

In this paper, we propose tools for modeling and evaluating our EQ-MAC protocol based on Stochastic Automata Networks (SAN) and Colored Petri Nets (CPN) model. EQ-MAC protocol is an energy efficient and quality of service aware medium access protocol designed for wireless sensor networks. To extract some results from the developed model, we used analytical resolution, GreatSPN and WNSIM tools. Results demonstrate the efficiency of our protocol. This work demonstrates the usefulness and the possibility of using SAN or CPN for modeling and evaluating any other MAC protocols for wireless sensor networks.

An Energy Efficient Priority-Based QoS MAC Protocol for Wireless Sensor Networks

In this paper we present an energy efficient priority based MAC protocol for Wireless Sensor Networks (WSNs). We abbreviate it as PRIMA. The PRIMA protocol consists of two phases; a clustering phase and a channel access phase. Clustering the senor network makes the MAC protocol to handle well network scalability issues. The channel access is composed of a hybrid mode of TDMA and CSMA. CSMA mode is used to communicate control messages, while data messages are assigned TDMA slots. Doing so, minimizes packet collisions and consequently minimizing energy consumption. Our PRIMA protocol forces the nodes that have no data to send to go early into a sleep state to save energy, this minimizes the idle listening periods which is considered as a main source of the energy consumption in sensor networks. The PRIMA protocol provides Quality of Service (QoS) by employing a queueing model to classify the traffic depending on its importance into four different queues. Higher priority queues have absolute preferential treatment over low priority queues. Through simulations and analytical analysis, we evaluate the performance of our proposed MAC protocol and compare it against the Q-MAC protocol. Results have shown that our protocol outperforms Q-MAC in terms of energy consumption, packet delivery ratio and average packet delay.

Performance Analysis of UGS, rtPS, nrtPS Admission Control in WiMAX Networks

IEEE 802.16 standard provides a broadband wireless access solution. WiMAX (Worldwide interpretability for microwave access) is the business definition of the 802.16-2004 amendment. In WiMAX, quality of service (QoS) is provided through both classification and scheduling of the four different types of traffic classes defined by the standard. Each class has it own bandwidth requirements as well as its level of QoS, which has to be maintained. In this paper, we provide a performance analysis of three types of connections defined in the standard (UGS, rtPS, nrtPS). Different levels of priority and blocking probability are assigned to each class of service. This performance analysis has been done using an analytical model for evaluating admission control (AC) for the previous mentioned classes in WiMAX network.

Admission control mechanism and performance analysis based on stochastic automata networks formalism

IEEE 802.16 has been designed to support QoS (Quality of Service) in Wireless broadband Metropolitan Networks (WMAN), and specifically in the access networks. To achieve this, the IEEE 802.16.e amendment introduces the service differentiation by five service classes (UGS, ertPS, rtPS, nrtPS and BE). To maintain the QoS of active connections and to avoid any congestion in the network, an Admission Control (AC) is defined. AC aims to accept or reject a new connection according to the negotiated parameters and the availability of resources in the network. This mechanism is not standardized and let to the operators. We tackle this point, by proposing in this study a new Admission Control (AC) that improves the QoS of BE traffic by avoiding a strict bandwidth assignment of other traffics (rtPS and nrtPS) as is defined in major previous studies. The proposed mechanism is based on token bucket for rtPS, nrtPS and BE traffics in order to reduce lightly the number of accepted connections and to improve considerably the number of accepted BE connections. To evaluate the performance of the proposed scheme, we use PEPS (Performance Evaluation of Parallel Systems) which is a powerful tool based on models which can be described with Stochastic Automata Networks (SAN). PEPS can solve complex models with a large state space and with many synchronized events. Therefore, we show that this tool is suitable for wireless network, and specifically for the proposed scheme, toward numerical results we show as we expected that our proposed AC outperform the classical one by reducing lightly the performance of other service classes.

Q-HWMP: Improving End-to-End QoS for 802.11s Based Mesh Networks

Wireless mesh network (WMNs) are an emerging technology, presented mainly as a way to build a multi-hop network based on an infrastructure. IEEE has developed a draft 802.11s describing the enhancement of the IEEE 802.11 for mesh networks. This new standard aims to create a new wireless configuration that manages the topology, the quality of radio link and the routing. For routing, two path selection protocols HWMP (Hybrid Wireless Mesh Protocol) and RA-OLSR (Radio-Aware Optimized Link State Routing) are considered. The both routing protocols are inadequate for multimedia applications, such as video conferencing, which is often requiring guaranteed Quality of Service (QoS). QoS routing requires not only finding a best route from a source to a destination according to some criteria (like AirTime metric, hop numbers, etc.) , which is the case of HWMP, but a route that satisfies the end-to-end QoS requirement, often given in terms of bandwidth or delay. This paper tackles this last point by improving the HWMP protocol that handles QoS for real time applications. The goal of the proposed enhancement is to increase the bandwidth utilization and to avoid any network congestions. The method is based on the evaluation of QoS parameters as end-to-end delay or remaining bandwidth and to determine if they can fit with the real time application. Simulation results show that the proposed solution outperform classical HWMP.

Dynamic solution for detecting Denial of Service attacks in wireless sensor networks

In this paper, we propose a novel dynamic approach for detecting Denial of Service (DoS) attacks in cluster-based sensor networks. Our method is based on the election of controller nodes called cNodes which observe and report DoS attack activities. Each cluster contains cNodes and normal sensor nodes. The role of a cNode is to analyze traffic and to send back a warning to the cluster head if any abnormal traffic is detected. The election of these cNodes is dynamic, and done periodically and based on a Multiplicative Linear-Congruential Generator (MLCG). The proposed dynamic solution can improve the network lifetime by minimizing the energy consumption for each sensor node and can improve security by preventing attacks.

DJAVAN: Detecting jamming attacks in Vehicle Ad hoc Networks

Abstract With development of wireless communications in the two last decades, new infrastructures have been developed. One of them is the Vehicular Ad hoc Networks (VANETs). They are considered as ad hoc networks with the particularity that the topology is always changed, that make more complicated the resource management and open some beaches in security. Specifically on the Physical and MAC layers that are more vulnerable as they are built on distributed systems and a fluctuating radio channel. Thus, it is not easy to know when transmitted data are not delivered to the destination, if this is due to an attack or to a propagation problem. In this study, we propose a new algorithm DJAVAN (solution of Detecting Jamming Attacks in Vehicle Ad Hoc Networks) to detect a jamming attack in VANETs using the Packet Delivery Ratio (PDR) and with the performance analysis, we determine the threshold that can make the difference between an attack and a poor radio link.

Performance analysis of a selective encryption algorithm for wireless ad hoc networks

Symmetric key algorithms are a typically efficient and fast cryptosystem, so it has significant applications in many realms. For a wireless ad hoc network with constraint computational resources, the cryptosystem based on symmetric key algorithms is extremely suitable for such an agile and dynamic environment, along with other security strategies. In this paper, we introduce the concept of selective encryption into the design of data protection mechanisms. First, we present the principle of selective encryption and propose a probabilistically selective encryption algorithm based on symmetric key. By utilizing probabilistic methodology and stochastic algorithm, a sender includes proper uncertainty in the process of message encryption, so that only entrusted receiver can decrypt the ciphertext and other unauthorized nodes have no knowledge of the transmitted messages on the whole. In addition, we also employ other security mechanisms to enhance the security of our proposed scheme. Eventually, we carry out an extensive set of simulation experiments based on ns2 simulator, and our simulation indicates that the technique of selective algorithms can indeed improve the efficiency of message encryption.