517 research outputs found
Quantum wiretap channel with non-uniform random number and its exponent and equivocation rate of leaked information
A usual code for quantum wiretap channel requires an auxiliary random
variable subject to the perfect uniform distribution. However, it is difficult
to prepare such an auxiliary random variable. We propose a code that requires
only an auxiliary random variable subject to a non-uniform distribution instead
of the perfect uniform distribution. Further, we evaluate the exponential
decreasing rate of leaked information and derive its equivocation rate. For
practical constructions, we also discuss the security when our code consists of
a linear error correcting code
Exponential decreasing rate of leaked information in universal random privacy amplification
We derive a new upper bound for Eve's information in secret key generation
from a common random number without communication. This bound improves on
Bennett et al(1995)'s bound based on the R\'enyi entropy of order 2 because the
bound obtained here uses the R\'enyi entropy of order for .
This bound is applied to a wire-tap channel. Then, we derive an exponential
upper bound for Eve's information. Our exponent is compared with
Hayashi(2006)'s exponent. For the additive case, the bound obtained here is
better. The result is applied to secret key agreement by public discussion.Comment: The organization is a little changed. This version is the same as the
published versio
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