Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A real-time QKD system based on FPGA   A real-time Quantum Key Distribution System is developed in this paper. In
the system, based on the feature of Field Programmable Gate Array (FPGA),
secure key extraction control and algorithm have been optimally designed to
perform sifting, error correction and privacy amplification altogether in
real-time. In the QKD experiment information synchronization mechanism and
high-speed classic data channel are designed to ensure the steady operation of
the system. Decoy state and synchronous laser light source are used in the
system, while the length of optical fiber between Alice and Bob is 20 km. With
photons repetition frequency of 20 MHz, the final key rate could reach 17 kbps.
Smooth and robust operation is verified with 6-hour continuous test and
associated with encrypted voice communication test.

18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
27
The categories of this paper are: comp-gas
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
32
The categories of this paper are: atom-ph
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
29
The categories of this paper are: funct-an
30
The categories of this paper are: q-alg
10
The categories of this paper are: q-bio