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Proceedings Paper

Informed guessing of an eavesdropper's Renyi entropy
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Paper Abstract

Users of a quantum cryptographic system face a problem of deciding on the ignorance of a maximally adroit eavesdropper concerning their key material. It is known that there can be no sure, positive, lower bound on any plausible measure of ignorance, and for this reason we characterize the problem as the making of an informed guess, meaning a guess that employs a rule that can be shown to work except in unlikely cases. As the measure of an eavesdropper's ignorance concerning n bits of sifted key material less some number k of bits found in error and discarded, we analyze Renyi entropy of arbitrary order R, for 1 ≤ R ≤ 2. We offer a rule for deciding on Renyi entropy based on a tighter bound on the relevant probability distributions than has been available. To this end, we employ a recently derived approximation to the cumulative binomial distribution which is uniformly accurate over a larger domain than previously available approximations. This results in a longer distilled key than that obtained from looser bounds, as well as generalizing the order R. Some numerical examples are presented.

Paper Details

Date Published: 4 August 2003
PDF: 8 pages
Proc. SPIE 5105, Quantum Information and Computation, (4 August 2003); doi: 10.1117/12.486994
Show Author Affiliations
John M. Myers, Harvard Univ. (United States)
Tai Tsun Wu, Harvard Univ. (United States)


Published in SPIE Proceedings Vol. 5105:
Quantum Information and Computation
Eric Donkor; Andrew R. Pirich; Howard E. Brandt, Editor(s)

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