Omar Alfandi

Towards robust key extraction from multipath wireless channels

This paper tackles the problem of generating shared secret keys based on the physical characteristics of the wireless channel. We propose intelligent quantization mechanisms for key generation, achieving high secret bits generation rate. Moreover, some practical issues affecting the performance of the key generation mechanism are deeply investigated. Mainly, we investigate the effects of delay and mobility on the performance and we enhance the key generation mechanism accordingly. As a result, this paper presents a framework towards robust key generation from multipath wireless channels.

A Survey on Measures for Secure Routing in Wireless Sensor Networks

In the near future, it is likely that wireless sensor networks (WSNs) become a major technology for the sensing in different application areas. One of the main challenges in WSNs is the secure routing of data through the network. This is resulting from the fact that WSNs are normally deployed in unattended or even hostile environments. While in last few years the routing approaches were mainly focussing on metrics such as robustness, energy preservation, etc., recently, different security solutions came to the fore that were taking also the security issues in WSNs into account. In this paper, different types of attacks on the routing layer of WSNs are investigated. Subsequently, measures for secure routing; including cryptography, key establishment, trust & reputation and secure localization; are reviewed, which were proposed by researchers in this area. Based on these findings, future prospects are discussed and final conclusions will be drawn.

Intelligent mechanisms for key generation from multipath wireless channels

The wireless communication channel has been found recently to have some interesting properties. In particular, it has been found that the multipath wireless channel can be leveraged for the purpose of key generation. In this paper, we investigate this property and propose an intelligent key generation method based on phase shifting and correction. Further, we discuss improvements of this approach and finally, we test our algorithm on a typical outdoor wireless channel. Our simulation results show that more than 90 bits can be generated from a single channel observation.

Graph-theoretic characterization of cyber-threat infrastructures

In this paper, we investigate cyber-threats and the underlying infrastructures. More precisely, we detect and analyze cyber-threat infrastructures for the purpose of unveiling key players (owners, domains, IPs, organizations, malware families, etc.) and the relationships between these players. To this end, we propose metrics to measure the badness of different infrastructure elements using graph theoretic concepts such as centrality concepts and Google PageRank. In addition, we quantify the sharing of infrastructure elements among different malware samples and families to unveil potential groups that are behind specific attacks. Moreover, we study the evolution of cyber-threat infrastructures over time to infer patterns of cyber-criminal activities. The proposed study provides the capability to derive insights and intelligence about cyber-threat infrastructures. Using one year dataset, we generate notable results regarding emerging threats and campaigns, important players behind threats, linkages between cyber-threat infrastructure elements, patterns of cyber-crimes, etc.

An optimal sensor deployment scheme to ensure multi level coverage and connectivity in wireless sensor networks

This paper introduces an optimal deployment algorithm of sensors in a given region to provide desired coverage and connectivity for a wireless sensor network. Our paper utilizes two separate procedures for covering different regions of a symmetrical rectangular area. The proposed method divides the given area of interest into two distinct sub-regions termed as the central and edge regions. In each region, a unique scheme is used to determine the number and location of sensors required to monitor and completely cover the region keeping the connectivity and coverage ranges of the sensors, their hardware specification and the dimensions of the region concerned as the constraints. Our scheme reduces the overhead in determining the position of sensors for deployment by following a coverage and connectivity algorithm of lesser complexity rather than those present in related schemes. Finally, we compare our deployment scheme with the interpolation scheme of [2] in regions of different dimensions and different coverage and connectivity levels with different sensing ranges of the sensors to show our cost efficiency over the latter.

Trust integrated link state routing protocol for Wireless Sensor Networks (TILSRP)

Several methods exist for the assignment of trust to the nodes present in a Wireless Sensor Network (WSN). In this paper we develop a new algorithm for calculation of trust of individual nodes using both Direct and Indirect Trusts and thereby use the calculated trusts for determination of the different route trusts (RTs) to the Base Station. We present a link state routing protocol based on trust which protects the WSN against routing attacks by eliminating the un-trusted nodes beforehand. It then forms the routes and finds the best trustworthy route among them by comparing the values of all the calculated route trusts as for each and every route present in the network. This paper also shows the advantage of inclusion of Indirect Trusts in addition to the Direct Trusts. Finally, we compare our work with the most prevalent routing protocols and show its benefits over them.

On improving the robustness of physical-layer key extraction mechanisms against delay and mobility

Recently, key extraction from multipath wireless channels has been largely investigated. This paper tackles practical issues affecting the reliability of key agreement. We first analyze the effect of delay between the channel estimates on the probability of disagreement, and we propose a robust key extraction mechanism against delay. Later, we study the effect of mobility and improve our key generation mechanism taking into account the decorrelation of the channel. Finally, we investigate the impact of mobility on the overall secret bit generation rate.

Efficient geographical 3D routing for Wireless Sensor Networks in smart spaces

Wireless Sensor Networks (WSNs) is one of the basic components in smart spaces. These kinds of networks are facing many challenges mainly due to limited resources. Indeed, routing protocols are one of the greatest challenges in this domain. Several 3D (Three Dimensions) routing protocols in real environment have been proposed for wireless sensor networks. Some are based on partial or full flooding schemes which consume more energy and incur higher communication overhead, or counted on construction or partition of cubes, convex hulls or Delaunay triangulations where their constructor are relatively complicated and additional cost could be required. In this paper, we present a simple efficient geographical 3D routing algorithm, efficient subminimal Ellipsoid geographical Greedy-Face 3D Routing (EGF3D). The algorithm is based on Greedy and Face routing strategies which are restricted in one subminimal ellipsoid fixed by three points: the forwarding endpoint node, the destination endpoint node and the subminimal angle neighbor in the favorable forwarding direction. We evaluate our approach and compare with the current routing algorithms in this domain. The simulation results show the competitive improvement delivery ratio, end-to-end delay and the communication overhead compared with greedy-random-greedy (GRG) and energy efficiency localized 3D greedy routing algorithm (ERGrd).

Secure and Authenticated Data Communication in Wireless Sensor Networks.

Securing communications in wireless sensor networks is increasingly important as the diversity of applications increases. However, even today, it is equally important for the measures employed to be energy efficient. For this reason, this publication analyzes the suitability of various cryptographic primitives for use in WSNs according to various criteria and, finally, describes a modular, PKI-based framework for confidential, authenticated, secure communications in which most suitable primitives can be employed. Due to the limited capabilities of common WSN motes, criteria for the selection of primitives are security, power efficiency and memory requirements. The implementation of the framework and the singular components have been tested and benchmarked in our testbed of IRISmotes.

The design and implementation of a wireless healthcare application for WSN-enabled IMS environments

The IP Multimedia Subsystem (IMS) is one of the key components of third generation (3G) networks, while Wireless Sensor Networks (WSNs) are an emerging type of networks formed by a set of distributed sensor nodes that collaborate to monitor environmental and physical conditions. Combining the capabilities of WSNs and the IMS opens the door to a wide range of personalized and adaptive value added services for 3G users. We have previously proposed a solution for WSN/IMS integration. This solution enriches the IMS architecture with context acquisition and management components, and enables access to those capabilities via standard IMS interfaces. Wireless healthcare is one of the important application areas that can benefit from the combined IMS/WSNs capabilities. In this paper, we focus on this application area and present a case study on the design and implementation of a context-aware IMS wireless healthcare application, that leverages the capabilities of our WSN/IMS integration solution. The applications detailed scenario and IMS deployment architecture are presented and a prototype is built and tested using Ericssons IMS simulated environment.