7,608 research outputs found
Resource Allocation for Secure Gaussian Parallel Relay Channels with Finite-Length Coding and Discrete Constellations
We investigate the transmission of a secret message from Alice to Bob in the
presence of an eavesdropper (Eve) and many of decode-and-forward relay nodes.
Each link comprises a set of parallel channels, modeling for example an
orthogonal frequency division multiplexing transmission. We consider the impact
of discrete constellations and finite-length coding, defining an achievable
secrecy rate under a constraint on the equivocation rate at Eve. Then we
propose a power and channel allocation algorithm that maximizes the achievable
secrecy rate by resorting to two coupled Gale-Shapley algorithms for stable
matching problem. We consider the scenarios of both full and partial channel
state information at Alice. In the latter case, we only guarantee an outage
secrecy rate, i.e., the rate of a message that remains secret with a given
probability. Numerical results are provided for Rayleigh fading channels in
terms of average outage secrecy rate, showing that practical schemes achieve a
performance quite close to that of ideal ones
PHYSICAL LAYER SECURITY FOR WIRELESS NETWORKS BASED ON COSET CONVOLUTIONAL CODING
This paper presents a new physical layer security for wireless networks using non-linear convolutional cryptosystem. Relevant performance metrics such as secret channel capacity and throughput are considered in the implementation. Secret channel capacity is implemented using confusion bits generated from coset convolutional coding while throughput is enhanced due to the forward error correction capability of convolutional codes. The paper establishes a method to determine wireless channel parameters for secure communication.It is shown that, the probability of correct decision of an eavesdropper is zero when appropriate values of M-PAM constellations, the number of transmitted bits, k and the signal-to-noise ratio (SNR) per bit in dB are chosen. In addition, it is shown that, the convolutional cryptosystem enhances security for the case where the eavesdropper probability of correct decision is not zero. The entire scheme applied to CDMA is ported to a Virtex 5 FPGA chip to circumvent poor key management due to additional keys used in the convolutional cryptosystem
Power Allocation and Time-Domain Artificial Noise Design for Wiretap OFDM with Discrete Inputs
Optimal power allocation for orthogonal frequency division multiplexing
(OFDM) wiretap channels with Gaussian channel inputs has already been studied
in some previous works from an information theoretical viewpoint. However,
these results are not sufficient for practical system design. One reason is
that discrete channel inputs, such as quadrature amplitude modulation (QAM)
signals, instead of Gaussian channel inputs, are deployed in current practical
wireless systems to maintain moderate peak transmission power and receiver
complexity. In this paper, we investigate the power allocation and artificial
noise design for OFDM wiretap channels with discrete channel inputs. We first
prove that the secrecy rate function for discrete channel inputs is nonconcave
with respect to the transmission power. To resolve the corresponding nonconvex
secrecy rate maximization problem, we develop a low-complexity power allocation
algorithm, which yields a duality gap diminishing in the order of
O(1/\sqrt{N}), where N is the number of subcarriers of OFDM. We then show that
independent frequency-domain artificial noise cannot improve the secrecy rate
of single-antenna wiretap channels. Towards this end, we propose a novel
time-domain artificial noise design which exploits temporal degrees of freedom
provided by the cyclic prefix of OFDM systems {to jam the eavesdropper and
boost the secrecy rate even with a single antenna at the transmitter}.
Numerical results are provided to illustrate the performance of the proposed
design schemes.Comment: 12 pages, 7 figures, accepted by IEEE Transactions on Wireless
Communications, Jan. 201
An Overview of Physical Layer Security with Finite-Alphabet Signaling
Providing secure communications over the physical layer with the objective of
achieving perfect secrecy without requiring a secret key has been receiving
growing attention within the past decade. The vast majority of the existing
studies in the area of physical layer security focus exclusively on the
scenarios where the channel inputs are Gaussian distributed. However, in
practice, the signals employed for transmission are drawn from discrete signal
constellations such as phase shift keying and quadrature amplitude modulation.
Hence, understanding the impact of the finite-alphabet input constraints and
designing secure transmission schemes under this assumption is a mandatory step
towards a practical implementation of physical layer security. With this
motivation, this article reviews recent developments on physical layer security
with finite-alphabet inputs. We explore transmit signal design algorithms for
single-antenna as well as multi-antenna wiretap channels under different
assumptions on the channel state information at the transmitter. Moreover, we
present a review of the recent results on secure transmission with discrete
signaling for various scenarios including multi-carrier transmission systems,
broadcast channels with confidential messages, cognitive multiple access and
relay networks. Throughout the article, we stress the important behavioral
differences of discrete versus Gaussian inputs in the context of the physical
layer security. We also present an overview of practical code construction over
Gaussian and fading wiretap channels, and we discuss some open problems and
directions for future research.Comment: Submitted to IEEE Communications Surveys & Tutorials (1st Revision
On Massive MIMO Physical Layer Cryptosystem
In this paper, we present a zero-forcing (ZF) attack on the physical layer
cryptography scheme based on massive multiple-input multiple-output (MIMO). The
scheme uses singular value decomposition (SVD) precoder. We show that the
eavesdropper can decrypt/decode the information data under the same condition
as the legitimate receiver. We then study the advantage for decoding by the
legitimate user over the eavesdropper in a generalized scheme using an
arbitrary precoder at the transmitter. On the negative side, we show that if
the eavesdropper uses a number of receive antennas much larger than the number
of legitimate user antennas, then there is no advantage, independent of the
precoding scheme employed at the transmitter. On the positive side, for the
case where the adversary is limited to have the same number of antennas as
legitimate users, we give an upper bound on the
advantage and show that this bound can be approached using an inverse precoder.Comment: To be presented at ITW 2015, Jeju Island, South Korea. 6 Pages, 1
Figur
- …