Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Practical security analysis of two-way quantum key distribution
  protocols based on non-orthogonal states   Within the broad research scenario of quantum secure communication, Two-Way
Quantum Key Distribution (TWQKD) is a relatively new proposal for sharing
secret keys that is not fully explored yet. We analyse the security of TWQKD
schemes that use qubits prepared in non-orthogonal states to transmit the key.
Investigating protocols that employ an arbitrary number of bases for the
channel preparation, we show, in particular, that the security of the LM05
protocol can not be improved by the use of more than two preparation bases. We
also provide a new proof of unconditional security for a deterministic TWQKD
protocol recently proposed [Phys. Rev. A 88, 062302 (2013)]. In addition, we
introduce a novel deterministic protocol named TWQKD six-state and compute an
analytical lower bound (which can be tightened) for the maximum amount of
information that an eavesdropper could extract in this case. An interesting
advantage of our approach to the security analysis of TWQKD is the great
simplicity and transparency of the derivations.

36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
33
The categories of this paper are: plasm-ph
8
The categories of this paper are: hep-ex
15
The categories of this paper are: nucl-ex
16
The categories of this paper are: stat
30
The categories of this paper are: q-alg
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
28
The categories of this paper are: alg-geom
7
The categories of this paper are: hep-th