177 research outputs found
Publicness, Privacy and Confidentiality in the Single-Serving Quantum Broadcast Channel
The 2-receiver broadcast channel is studied: a network with three parties
where the transmitter and one of the receivers are the primarily involved
parties and the other receiver considered as third party. The messages that are
determined to be communicated are classified into public, private and
confidential based on the information they convey. The public message contains
information intended for both parties and is required to be decoded correctly
by both of them, the private message is intended for the primary party only,
however, there is no secrecy requirement imposed upon it meaning that it can
possibly be exposed to the third party and finally the confidential message
containing information intended exclusively for the primary party such that
this information must be kept completely secret from the other receiver. A
trade-off arises between the rates of the three messages, when one of the rates
is high, the other rates may need to be reduced to guarantee the reliable
transmission of all three messages. The encoder performs the necessary
equivocation by virtue of dummy random numbers whose rate is assumed to be
limited and should be considered in the trade-off as well. We study this
trade-off in the one-shot regime of a quantum broadcast channel by providing
achievability and (weak) converse regions. In the achievability, we prove and
use a conditional version of the convex-split lemma as well as position-based
decoding. By studying the asymptotic behaviour of our bounds, we will recover
several well-known asymptotic results in the literature.Comment: 23 pages, 1 figure, journa
Coding Schemes for Achieving Strong Secrecy at Negligible Cost
We study the problem of achieving strong secrecy over wiretap channels at
negligible cost, in the sense of maintaining the overall communication rate of
the same channel without secrecy constraints. Specifically, we propose and
analyze two source-channel coding architectures, in which secrecy is achieved
by multiplexing public and confidential messages. In both cases, our main
contribution is to show that secrecy can be achieved without compromising
communication rate and by requiring only randomness of asymptotically vanishing
rate. Our first source-channel coding architecture relies on a modified wiretap
channel code, in which randomization is performed using the output of a source
code. In contrast, our second architecture relies on a standard wiretap code
combined with a modified source code termed uniform compression code, in which
a small shared secret seed is used to enhance the uniformity of the source code
output. We carry out a detailed analysis of uniform compression codes and
characterize the optimal size of the shared seed.Comment: 15 pages, two-column, 5 figures, accepted to IEEE Transactions on
Information Theor
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
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
- …