74,246 research outputs found
Increasing Physical Layer Security through Scrambled Codes and ARQ
We develop the proposal of non-systematic channel codes on the AWGN wire-tap
channel. Such coding technique, based on scrambling, achieves high transmission
security with a small degradation of the eavesdropper's channel with respect to
the legitimate receiver's channel. In this paper, we show that, by implementing
scrambling and descrambling on blocks of concatenated frames, rather than on
single frames, the channel degradation needed is further reduced. The usage of
concatenated scrambling allows to achieve security also when both receivers
experience the same channel quality. However, in this case, the introduction of
an ARQ protocol with authentication is needed.Comment: 5 pages, 4 figures; Proc. IEEE ICC 2011, Kyoto, Japan, 5-9 June 201
Secure Communication Using Non-systematic Error Control Codes
A transmitter device (110T) for secure communication includes: an encoder (170) configured to apply a non-systematic error correcting code (NS ECC) to a message, thus producing encoded bits with no clear message bits; and a transceiver (720) configured to transmit the encoded bits over a main channel to a receiver. A method for secure communication includes: encoding a message with an NS ECC to produce an encoded message carrying no message bits in the clear; and transmitting the encoded message over a main channel (120). The NS ECC characteristics result in an eavesdropper channel error probability under a security threshold (320) and a main channel error probability over a reliability threshold (310), whenever an eavesdropper (140) listening on an eavesdropper channel (150) is more than distance Z (220) from the transmitter. Unreliable bits in the encoded bits render the eavesdropper unable to reliably decode messages on the main channel.Georgia Tech Research CorporationKorea Advanced Institute Of Science And Technolog
Coding with Scrambling, Concatenation, and HARQ for the AWGN Wire-Tap Channel: A Security Gap Analysis
This study examines the use of nonsystematic channel codes to obtain secure
transmissions over the additive white Gaussian noise (AWGN) wire-tap channel.
Unlike the previous approaches, we propose to implement nonsystematic coded
transmission by scrambling the information bits, and characterize the bit error
rate of scrambled transmissions through theoretical arguments and numerical
simulations. We have focused on some examples of Bose-Chaudhuri-Hocquenghem
(BCH) and low-density parity-check (LDPC) codes to estimate the security gap,
which we have used as a measure of physical layer security, in addition to the
bit error rate. Based on a number of numerical examples, we found that such a
transmission technique can outperform alternative solutions. In fact, when an
eavesdropper (Eve) has a worse channel than the authorized user (Bob), the
security gap required to reach a given level of security is very small. The
amount of degradation of Eve's channel with respect to Bob's that is needed to
achieve sufficient security can be further reduced by implementing scrambling
and descrambling operations on blocks of frames, rather than on single frames.
While Eve's channel has a quality equal to or better than that of Bob's
channel, we have shown that the use of a hybrid automatic repeat-request (HARQ)
protocol with authentication still allows achieving a sufficient level of
security. Finally, the secrecy performance of some practical schemes has also
been measured in terms of the equivocation rate about the message at the
eavesdropper and compared with that of ideal codes.Comment: 29 pages, 10 figure
LDPC Code Design for the BPSK-constrained Gaussian Wiretap Channel
A coding scheme based on irregular low-density parity-check (LDPC) codes is
proposed to send secret messages from a source over the Gaussian wiretap
channel to a destination in the presence of a wiretapper, with the restriction
that the source can send only binary phase-shift keyed (BPSK) symbols. The
secrecy performance of the proposed coding scheme is measured by the secret
message rate through the wiretap channel as well as the equivocation rate about
the message at the wiretapper. A code search procedure is suggested to obtain
irregular LDPC codes that achieve good secrecy performance in such context.Comment: submitted to IEEE GLOBECOM 2011 - Communication Theory Symposiu
LDPC coded transmissions over the Gaussian broadcast channel with confidential messages
We design and assess some practical low-density parity-check (LDPC) coded
transmission schemes for the Gaussian broadcast channel with confidential
messages (BCC). This channel model is different from the classical wiretap
channel model as the unauthorized receiver (Eve) must be able to decode some
part of the information. Hence, the reliability and security targets are
different from those of the wiretap channel. In order to design and assess
practical coding schemes, we use the error rate as a metric of the performance
achieved by the authorized receiver (Bob) and the unauthorized receiver (Eve).
We study the system feasibility, and show that two different levels of
protection against noise are required on the public and the secret messages.
This can be achieved in two ways: i) by using LDPC codes with unequal error
protection (UEP) of the transmitted information bits or ii) by using two
classical non-UEP LDPC codes with different rates. We compare these two
approaches and show that, for the considered examples, the solution exploiting
UEP LDPC codes is more efficient than that using non-UEP LDPC codes.Comment: 5 pages, 5 figures, to be presented at IEEE ICT 201
Practical LDPC coded modulation schemes for the fading broadcast channel with confidential messages
The broadcast channel with confidential messages is a well studied scenario
from the theoretical standpoint, but there is still lack of practical schemes
able to achieve some fixed level of reliability and security over such a
channel. In this paper, we consider a quasi-static fading channel in which both
public and private messages must be sent from the transmitter to the receivers,
and we aim at designing suitable coding and modulation schemes to achieve such
a target. For this purpose, we adopt the error rate as a metric, by considering
that reliability (security) is achieved when a sufficiently low (high) error
rate is experienced at the receiving side. We show that some conditions exist
on the system feasibility, and that some outage probability must be tolerated
to cope with the fading nature of the channel. The proposed solution exploits
low-density parity-check codes with unequal error protection, which are able to
guarantee two different levels of protection against noise for the public and
the private information, in conjunction with different modulation schemes for
the public and the private message bits.Comment: 6 pages, 4 figures, to be presented at IEEE ICC'14 - Workshop on
Wireless Physical Layer Securit
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