591 research outputs found
Wiretap and Gelfand-Pinsker Channels Analogy and its Applications
An analogy framework between wiretap channels (WTCs) and state-dependent
point-to-point channels with non-causal encoder channel state information
(referred to as Gelfand-Pinker channels (GPCs)) is proposed. A good sequence of
stealth-wiretap codes is shown to induce a good sequence of codes for a
corresponding GPC. Consequently, the framework enables exploiting existing
results for GPCs to produce converse proofs for their wiretap analogs. The
analogy readily extends to multiuser broadcasting scenarios, encompassing
broadcast channels (BCs) with deterministic components, degradation ordering
between users, and BCs with cooperative receivers. Given a wiretap BC (WTBC)
with two receivers and one eavesdropper, an analogous Gelfand-Pinsker BC (GPBC)
is constructed by converting the eavesdropper's observation sequence into a
state sequence with an appropriate product distribution (induced by the
stealth-wiretap code for the WTBC), and non-causally revealing the states to
the encoder. The transition matrix of the state-dependent GPBC is extracted
from WTBC's transition law, with the eavesdropper's output playing the role of
the channel state. Past capacity results for the semi-deterministic (SD) GPBC
and the physically-degraded (PD) GPBC with an informed receiver are leveraged
to furnish analogy-based converse proofs for the analogous WTBC setups. This
characterizes the secrecy-capacity regions of the SD-WTBC and the PD-WTBC, in
which the stronger receiver also observes the eavesdropper's channel output.
These derivations exemplify how the wiretap-GP analogy enables translating
results on one problem into advances in the study of the other
Secret-key Agreement with Channel State Information at the Transmitter
We study the capacity of secret-key agreement over a wiretap channel with
state parameters. The transmitter communicates to the legitimate receiver and
the eavesdropper over a discrete memoryless wiretap channel with a memoryless
state sequence. The transmitter and the legitimate receiver generate a shared
secret key, that remains secret from the eavesdropper. No public discussion
channel is available. The state sequence is known noncausally to the
transmitter. We derive lower and upper bounds on the secret-key capacity. The
lower bound involves constructing a common state reconstruction sequence at the
legitimate terminals and binning the set of reconstruction sequences to obtain
the secret-key. For the special case of Gaussian channels with additive
interference (secret-keys from dirty paper channel) our bounds differ by 0.5
bit/symbol and coincide in the high signal-to-noise-ratio and high
interference-to-noise-ratio regimes. For the case when the legitimate receiver
is also revealed the state sequence, we establish that our lower bound achieves
the the secret-key capacity. In addition, for this special case, we also
propose another scheme that attains the capacity and requires only causal side
information at the transmitter and the receiver.Comment: 10 Pages, Submitted to IEEE Transactions on Information Forensics and
Security, Special Issue on Using the Physical Layer for Securing the Next
Generation of Communication System
Secure communication over fully quantum Gel'fand-Pinsker wiretap channel
In this work we study the problem of secure communication over a fully
quantum Gel'fand-Pinsker channel. The best known achievability rate for this
channel model in the classical case was proven by Goldfeld, Cuff and Permuter
in [Goldfeld, Cuff, Permuter, 2016]. We generalize the result of [Goldfeld,
Cuff, Permuter, 2016]. One key feature of the results obtained in this work is
that all the bounds obtained are in terms of error exponent. We obtain our
achievability result via the technique of simultaneous pinching. This in turn
allows us to show the existence of a simultaneous decoder. Further, to obtain
our encoding technique and to prove the security feature of our coding scheme
we prove a bivariate classical-quantum channel resolvability lemma and a
conditional classical-quantum channel resolvability lemma. As a by product of
the achievability result obtained in this work, we also obtain an achievable
rate for a fully quantum Gel'fand-Pinsker channel in the absence of Eve. The
form of this achievable rate matches with its classical counterpart. The
Gel'fand-Pinsker channel model had earlier only been studied for the
classical-quantum case and in the case where Alice (the sender) and Bob (the
receiver) have shared entanglement between them.Comment: version 2, 1 figure, 26 pages, added some extra proof and corrected
few typo
- …