25,605 research outputs found
Evaluating On-demand Pseudonym Acquisition Policies in Vehicular Communication Systems
Standardization and harmonization efforts have reached a consensus towards
using a special-purpose Vehicular Public-Key Infrastructure (VPKI) in upcoming
Vehicular Communication (VC) systems. However, there are still several
technical challenges with no conclusive answers; one such an important yet open
challenge is the acquisition of shortterm credentials, pseudonym: how should
each vehicle interact with the VPKI, e.g., how frequently and for how long?
Should each vehicle itself determine the pseudonym lifetime? Answering these
questions is far from trivial. Each choice can affect both the user privacy and
the system performance and possibly, as a result, its security. In this paper,
we make a novel systematic effort to address this multifaceted question. We
craft three generally applicable policies and experimentally evaluate the VPKI
system performance, leveraging two large-scale mobility datasets. We consider
the most promising, in terms of efficiency, pseudonym acquisition policies; we
find that within this class of policies, the most promising policy in terms of
privacy protection can be supported with moderate overhead. Moreover, in all
cases, this work is the first to provide tangible evidence that the
state-of-the-art VPKI can serve sizable areas or domain with modest computing
resources.Comment: 6 pages, 7 figures, IoV-VoI'1
Lightweight Blockchain Framework for Location-aware Peer-to-Peer Energy Trading
Peer-to-Peer (P2P) energy trading can facilitate integration of a large
number of small-scale producers and consumers into energy markets.
Decentralized management of these new market participants is challenging in
terms of market settlement, participant reputation and consideration of grid
constraints. This paper proposes a blockchain-enabled framework for P2P energy
trading among producer and consumer agents in a smart grid. A fully
decentralized market settlement mechanism is designed, which does not rely on a
centralized entity to settle the market and encourages producers and consumers
to negotiate on energy trading with their nearby agents truthfully. To this
end, the electrical distance of agents is considered in the pricing mechanism
to encourage agents to trade with their neighboring agents. In addition, a
reputation factor is considered for each agent, reflecting its past performance
in delivering the committed energy. Before starting the negotiation, agents
select their trading partners based on their preferences over the reputation
and proximity of the trading partners. An Anonymous Proof of Location (A-PoL)
algorithm is proposed that allows agents to prove their location without
revealing their real identity. The practicality of the proposed framework is
illustrated through several case studies, and its security and privacy are
analyzed in detail
Artificial-Noise-Aided Secure Multi-Antenna Transmission with Limited Feedback
We present an optimized secure multi-antenna transmission approach based on
artificial-noise-aided beamforming, with limited feedback from a desired
single-antenna receiver. To deal with beamformer quantization errors as well as
unknown eavesdropper channel characteristics, our approach is aimed at
maximizing throughput under dual performance constraints - a connection outage
constraint on the desired communication channel and a secrecy outage constraint
to guard against eavesdropping. We propose an adaptive transmission strategy
that judiciously selects the wiretap coding parameters, as well as the power
allocation between the artificial noise and the information signal. This
optimized solution reveals several important differences with respect to
solutions designed previously under the assumption of perfect feedback. We also
investigate the problem of how to most efficiently utilize the feedback bits.
The simulation results indicate that a good design strategy is to use
approximately 20% of these bits to quantize the channel gain information, with
the remainder to quantize the channel direction, and this allocation is largely
insensitive to the secrecy outage constraint imposed. In addition, we find that
8 feedback bits per transmit antenna is sufficient to achieve approximately 90%
of the throughput attainable with perfect feedback.Comment: to appear in IEEE Transactions on Wireless Communication
A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends
This paper examines the security vulnerabilities and threats imposed by the
inherent open nature of wireless communications and to devise efficient defense
mechanisms for improving the wireless network security. We first summarize the
security requirements of wireless networks, including their authenticity,
confidentiality, integrity and availability issues. Next, a comprehensive
overview of security attacks encountered in wireless networks is presented in
view of the network protocol architecture, where the potential security threats
are discussed at each protocol layer. We also provide a survey of the existing
security protocols and algorithms that are adopted in the existing wireless
network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term
evolution (LTE) systems. Then, we discuss the state-of-the-art in
physical-layer security, which is an emerging technique of securing the open
communications environment against eavesdropping attacks at the physical layer.
We also introduce the family of various jamming attacks and their
counter-measures, including the constant jammer, intermittent jammer, reactive
jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the
integration of physical-layer security into existing authentication and
cryptography mechanisms for further securing wireless networks. Finally, some
technical challenges which remain unresolved at the time of writing are
summarized and the future trends in wireless security are discussed.Comment: 36 pages. Accepted to Appear in Proceedings of the IEEE, 201
On the Secrecy Capacity of Fading Channels
We consider the secure transmission of information over an ergodic fading
channel in the presence of an eavesdropper. Our eavesdropper can be viewed as
the wireless counterpart of Wyner's wiretapper. The secrecy capacity of such a
system is characterized under the assumption of asymptotically long coherence
intervals. We first consider the full Channel State Information (CSI) case,
where the transmitter has access to the channel gains of the legitimate
receiver and the eavesdropper. The secrecy capacity under this full CSI
assumption serves as an upper bound for the secrecy capacity when only the CSI
of the legitimate receiver is known at the transmitter, which is characterized
next. In each scenario, the perfect secrecy capacity is obtained along with the
optimal power and rate allocation strategies. We then propose a low-complexity
on/off power allocation strategy that achieves near-optimal performance with
only the main channel CSI. More specifically, this scheme is shown to be
asymptotically optimal as the average SNR goes to infinity, and interestingly,
is shown to attain the secrecy capacity under the full CSI assumption.
Remarkably, our results reveal the positive impact of fading on the secrecy
capacity and establish the critical role of rate adaptation, based on the main
channel CSI, in facilitating secure communications over slow fading channels.Comment: 18 pages, 3 figures, Submitted to the IEEE Trans. on Information
Theor
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