624 research outputs found
Construction of Codes for Wiretap Channel and Secret Key Agreement from Correlated Source Outputs by Using Sparse Matrices
The aim of this paper is to prove coding theorems for the wiretap channel
coding problem and secret key agreement problem based on the the notion of a
hash property for an ensemble of functions. These theorems imply that codes
using sparse matrices can achieve the optimal rate. Furthermore, fixed-rate
universal coding theorems for a wiretap channel and a secret key agreement are
also proved.Comment: A part of this paper is presented in part at 2009 IEEE Information
Theory Workshop (ITW2009), Taormina, Italy, pp.105-109, 2009. This paper is
submitted to IEEE Transactions on Information Theory. 34 page
Strongly Secure Communications Over the Two-Way Wiretap Channel
We consider the problem of secure communications over the two-way wiretap
channel under a strong secrecy criterion. We improve existing results by
developing an achievable region based on strategies that exploit both the
interference at the eavesdropper's terminal and cooperation between legitimate
users. We leverage the notion of channel resolvability for the multiple-access
channel to analyze cooperative jamming and we show that the artificial noise
created by cooperative jamming induces a source of common randomness that can
be used for secret-key agreement. We illustrate the gain provided by this
coding technique in the case of the Gaussian two-way wiretap channel, and we
show significant improvements for some channel configurations.Comment: 11 pages, 7 figures, submitted to IEEE Transactions on Information
Forensics and Security, Special Issue: "Using the Physical Layer for Securing
the Next Generation of Communication Systems
Guessing a password over a wireless channel (on the effect of noise non-uniformity)
A string is sent over a noisy channel that erases some of its characters.
Knowing the statistical properties of the string's source and which characters
were erased, a listener that is equipped with an ability to test the veracity
of a string, one string at a time, wishes to fill in the missing pieces. Here
we characterize the influence of the stochastic properties of both the string's
source and the noise on the channel on the distribution of the number of
attempts required to identify the string, its guesswork. In particular, we
establish that the average noise on the channel is not a determining factor for
the average guesswork and illustrate simple settings where one recipient with,
on average, a better channel than another recipient, has higher average
guesswork. These results stand in contrast to those for the capacity of wiretap
channels and suggest the use of techniques such as friendly jamming with
pseudo-random sequences to exploit this guesswork behavior.Comment: Asilomar Conference on Signals, Systems & Computers, 201
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