Authors: Alexey E Rastegin
Publish Date: 2015/12/10
Volume: 15, Issue: 3, Pages: 1225-1239
Abstract
We address the question of quantifying eavesdropper’s information gain in an individual attack on systems of quantum key distribution It is connected with the concept of conclusive eavesdropping introduced by Brandt Using the BB84 protocol we examine the problem of estimating a performance of conclusive entangling probe The question of interest depends on the choice of a quantitative measure of eavesdropper’s information about the errorfree sifted bits The Fuchs–Peres–Brandt probe realizes a very powerful individual attack on the BB84 scheme In the usual formulation Eve utilizes the Helstrom scheme in distinguishing between the two output probe states In conclusive eavesdropping the unambiguous discrimination is used Comparing these two versions allows to demonstrate serious distinctions between widely used quantifiers of mutual information In particular the socalled Rényi mutual information does not seem to be a completely legitimate measure of an amount of mutual information It is brightly emphasized with the example of conclusive eavesdropping
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