Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: General method for the security analysis in a quantum direct
  communication protocol   We introduce a general approach for the analysis of a quantum direct
communication protocol. The method is based on the investigation of the
superoperator acting on a joint system of the communicating parties and the
eavesdropper. The introduced method is more versatile than the approaches used
so far as it permits to incorporate different noise models in a unified way.
Moreover, it make use of a well grounded theory of quantum discrimination for
the purpose of estimating the eavesdropper's information gain.

24
The categories of this paper are: dg-ga
2
The categories of this paper are: math
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
11
The categories of this paper are: hep-lat
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th