Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Eavesdropping on practical quantum cryptography   Practical implementations of quantum cryptography use attenuated laser pulses
as the signal source rather than single photons. The channels used to transmit
are also lossy. Here we give a simple derivation of two beam-splitting attacks
on quantum cryptographic systems using laser pulses, either coherent or mixed
states with any mean photon number. We also give a simple derivation of a
photon-number splitting attack, the most advanced, both in terms of performance
and technology required. We find bounds on the maximum disturbance for a given
mean photon number and observed channel transmission efficiency for which a
secret key can be distilled. We start by reviewing two incoherent attacks that
can be used on single photon quantum cryptographic systems. These results are
then adapted to systems that use laser pulses and lossy channels.

25
The categories of this paper are: patt-sol
31
The categories of this paper are: ao-sci
27
The categories of this paper are: comp-gas
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
9
The categories of this paper are: nlin