2,036 research outputs found
On the tradeoff between privacy and energy in wireless sensor networks
Source location privacy is becoming an increasingly important property of some wireless sensor network applica- tions. The fake source technique has been proposed as an approach for handling the source location privacy problem in these situations. However, whilst the efficiency of the fake source techniques is well documented, there are several factors that limit the usefulness of current results: (i) the assumption that fake sources are known a priori, (ii) the selection of fake sources based on an prohibitively expensive pre-configuration phase and (iii) the lack of a commonly adopted attacker model. In this paper we address these limitations by investigating the efficiency of the fake source technique with respect to possible implementations, configurations and extensions that do not require a pre-configuration phase or a priori knowledge of fake sources. The results presented demonstrate that one possible implementation, in presence of a single attacker, can lead to a decrease in capture ratio of up to 60% when compared with a flooding baseline. In the presence of multiple attackers, the same implementation yields only a 30% decrease in capture ratio with respect to the same baseline. To address this problem we investigate a hybrid technique, known as phantom routing with fake sources, which achieves a corresponding 50% reduction in capture ratio
Software Defined Networks based Smart Grid Communication: A Comprehensive Survey
The current power grid is no longer a feasible solution due to
ever-increasing user demand of electricity, old infrastructure, and reliability
issues and thus require transformation to a better grid a.k.a., smart grid
(SG). The key features that distinguish SG from the conventional electrical
power grid are its capability to perform two-way communication, demand side
management, and real time pricing. Despite all these advantages that SG will
bring, there are certain issues which are specific to SG communication system.
For instance, network management of current SG systems is complex, time
consuming, and done manually. Moreover, SG communication (SGC) system is built
on different vendor specific devices and protocols. Therefore, the current SG
systems are not protocol independent, thus leading to interoperability issue.
Software defined network (SDN) has been proposed to monitor and manage the
communication networks globally. This article serves as a comprehensive survey
on SDN-based SGC. In this article, we first discuss taxonomy of advantages of
SDNbased SGC.We then discuss SDN-based SGC architectures, along with case
studies. Our article provides an in-depth discussion on routing schemes for
SDN-based SGC. We also provide detailed survey of security and privacy schemes
applied to SDN-based SGC. We furthermore present challenges, open issues, and
future research directions related to SDN-based SGC.Comment: Accepte
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
Secure Routing in Wireless Mesh Networks
Wireless mesh networks (WMNs) have emerged as a promising concept to meet the
challenges in next-generation networks such as providing flexible, adaptive,
and reconfigurable architecture while offering cost-effective solutions to the
service providers. Unlike traditional Wi-Fi networks, with each access point
(AP) connected to the wired network, in WMNs only a subset of the APs are
required to be connected to the wired network. The APs that are connected to
the wired network are called the Internet gateways (IGWs), while the APs that
do not have wired connections are called the mesh routers (MRs). The MRs are
connected to the IGWs using multi-hop communication. The IGWs provide access to
conventional clients and interconnect ad hoc, sensor, cellular, and other
networks to the Internet. However, most of the existing routing protocols for
WMNs are extensions of protocols originally designed for mobile ad hoc networks
(MANETs) and thus they perform sub-optimally. Moreover, most routing protocols
for WMNs are designed without security issues in mind, where the nodes are all
assumed to be honest. In practical deployment scenarios, this assumption does
not hold. This chapter provides a comprehensive overview of security issues in
WMNs and then particularly focuses on secure routing in these networks. First,
it identifies security vulnerabilities in the medium access control (MAC) and
the network layers. Various possibilities of compromising data confidentiality,
data integrity, replay attacks and offline cryptanalysis are also discussed.
Then various types of attacks in the MAC and the network layers are discussed.
After enumerating the various types of attacks on the MAC and the network
layer, the chapter briefly discusses on some of the preventive mechanisms for
these attacks.Comment: 44 pages, 17 figures, 5 table
Optical code-division multiple access system and optical signal processing
This thesis presents our recent researches on the development of coding devices, the
investigation of security and the design of systems in the optical cod-division multiple
access (OCDMA) systems. Besides, the techniques of nonlinear signal processing used
in the OCDMA systems fire our imagination, thus some researches on all-optical signal
processing are carried out and also summarized in this thesis.
Two fiber Bragg grating (FBG) based coding devices are proposed. The first coding
device is a superstructured FBG (SSFBG) using ±π/2-phase shifts instead of
conventional 0/π-phase shifts. The ±π/2-phase-shifted SSFBG en/decoders can not only
conceal optical codes well in the encoded signals but also realize the reutilization of
available codes by hybrid use with conventional 0/π-phase-shifted SSFBG en/decoders.
The second FBG based coding device is synthesized by layer-peeling method, which
can be used for simultaneous optical code recognition and chromatic dispersion
compensation.
Then, two eavesdropping schemes, one-bit delay interference detection and
differential detection, are demonstrated to reveal the security vulnerability of differential
phase-shift keying (DPSK) and code-shift keying (CSK) OCDMA systems.
To address the security issue as well as increase the transmission capacity, an
orthogonal modulation format based on DPSK and CSK is introduced into the OCDMA
systems. A 2 bit/symbol 10 Gsymbol/s transmission system using the orthogonal
modulation format is achieved. The security of the system can be partially guaranteed.
Furthermore, a fully-asynchronous gigabit-symmetric OCDMA passive optical
network (PON) is proposed, in which a self-clocked time gate is employed for signal
regeneration. A remodulation scheme is used in the PON, which let downstream and
upstream share the same optical carrier, allowing optical network units source-free. An
error-free 4-user 10 Gbit/s/user duplex transmission over 50 km distance is reazlied.
A versatile waveform generation scheme is then studied. A theoretical model is
established and a waveform prediction algorithm is summarized. In the demonstration,
various waveforms are generated including short pulse, trapezoidal, triangular and
sawtooth waveforms and doublet pulse.
ii
In addition, an all-optical simultaneous half-addition and half-subtraction scheme is
achieved at an operating rate of 10 GHz by using only two semiconductor optical
amplifiers (SOA) without any assist light.
Lastly, two modulation format conversion schemes are demonstrated. The first
conversion is from NRZ-OOK to PSK-Manchester coding format using a SOA based
Mach-Zehnder interferometer. The second conversion is from RZ-DQPSK to RZ-OOK
by employing a supercontinuum based optical thresholder
Quantum Key Distribution
This chapter describes the application of lasers, specifically diode lasers,
in the area of quantum key distribution (QKD). First, we motivate the
distribution of cryptographic keys based on quantum physical properties of
light, give a brief introduction to QKD assuming the reader has no or very
little knowledge about cryptography, and briefly present the state-of-the-art
of QKD. In the second half of the chapter we describe, as an example of a
real-world QKD system, the system deployed between the University of Calgary
and SAIT Polytechnic. We conclude the chapter with a brief discussion of
quantum networks and future steps.Comment: 20 pages, 12 figure
A Comprehensive Survey on the Cyber-Security of Smart Grids: Cyber-Attacks, Detection, Countermeasure Techniques, and Future Directions
One of the significant challenges that smart grid networks face is
cyber-security. Several studies have been conducted to highlight those security
challenges. However, the majority of these surveys classify attacks based on
the security requirements, confidentiality, integrity, and availability,
without taking into consideration the accountability requirement. In addition,
some of these surveys focused on the Transmission Control Protocol/Internet
Protocol (TCP/IP) model, which does not differentiate between the application,
session, and presentation and the data link and physical layers of the Open
System Interconnection (OSI) model. In this survey paper, we provide a
classification of attacks based on the OSI model and discuss in more detail the
cyber-attacks that can target the different layers of smart grid networks
communication. We also propose new classifications for the detection and
countermeasure techniques and describe existing techniques under each category.
Finally, we discuss challenges and future research directions
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