332 research outputs found
A decoding algorithm for Twisted Gabidulin codes
In this work, we modify the decoding algorithm for subspace codes by Koetter
and Kschischang to get a decoding algorithm for (generalized) twisted Gabidulin
codes. The decoding algorithm we present applies to cases where the code is
linear over the base field but not linear over
.Comment: This paper was submitted to ISIT 201
Coding Solutions for the Secure Biometric Storage Problem
The paper studies the problem of securely storing biometric passwords, such
as fingerprints and irises. With the help of coding theory Juels and Wattenberg
derived in 1999 a scheme where similar input strings will be accepted as the
same biometric. In the same time nothing could be learned from the stored data.
They called their scheme a "fuzzy commitment scheme". In this paper we will
revisit the solution of Juels and Wattenberg and we will provide answers to two
important questions: What type of error-correcting codes should be used and
what happens if biometric templates are not uniformly distributed, i.e. the
biometric data come with redundancy. Answering the first question will lead us
to the search for low-rate large-minimum distance error-correcting codes which
come with efficient decoding algorithms up to the designed distance. In order
to answer the second question we relate the rate required with a quantity
connected to the "entropy" of the string, trying to estimate a sort of
"capacity", if we want to see a flavor of the converse of Shannon's noisy
coding theorem. Finally we deal with side-problems arising in a practical
implementation and we propose a possible solution to the main one that seems to
have so far prevented real life applications of the fuzzy scheme, as far as we
know.Comment: the final version appeared in Proceedings Information Theory Workshop
(ITW) 2010, IEEE copyrigh
A Polynomial Description of the Rijndael Advanced Encryption Standard
The paper gives a polynomial description of the Rijndael Advanced Encryption
Standard recently adopted by the National Institute of Standards and
Technology. Special attention is given to the structure of the S-Box.Comment: 12 pages, LaTe
Unitary Space Time Constellation Analysis: An Upper Bound for the Diversity
The diversity product and the diversity sum are two very important parameters
for a good-performing unitary space time constellation. A basic question is
what the maximal diversity product (or sum) is. In this paper we are going to
derive general upper bounds on the diversity sum and the diversity product for
unitary constellations of any dimension and any size using packing
techniques on the compact Lie group U(n).Comment: 15 pages, 3 figures, submitted to IEEE trans. inf
A Numerical Approach for Designing Unitary Space Time Codes with Large Diversity
A numerical approach to design unitary constellation for any dimension and
any transmission rate under non-coherent Rayleigh flat fading channel.Comment: 32 pages, 6 figure
Some Remarks on Real and Complex Output Feedback
We provide some new necessary and sufficient conditions which guarantee
arbitrary pole placement of a particular linear system over the complex
numbers. We exhibit a non-trivial real linear system which is not controllable
by real static output feedback and discuss a conjecture from algebraic geometry
concerning the existence of real linear systems for which all static feedback
laws are real
A Complete Characterization of Irreducible Cyclic Orbit Codes
We give a complete list of orbit codes that are generated by an irreducible
cyclic group, i.e. an irreducible group having one generator. We derive some of
the basic properties of these codes such as the cardinality and the minimum
distance.Comment: in Proceedings of The Seventh International Workshop on Coding and
Cryptography 2011 April 11-15 2011, Paris, Franc
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