Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Face Flashing: a Secure Liveness Detection Protocol based on Light
  Reflections
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
36
The categories of this paper are: cmp-lg
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
20
The categories of this paper are: acc-phys
7
The categories of this paper are: hep-th
3
The categories of this paper are: physics
30
The categories of this paper are: q-alg