Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Piggybank Protocol for Quantum Cryptography   This paper presents a quantum mechanical version of the piggy-bank
cryptography protocol. The basic piggybank cryptography idea is to use two
communications: one with the encrypted message, and the other regarding the
encryption transformation which the receiver must decipher first. In the
quantum mechanical version of the protocol, the encrypting unitary
transformation information is sent separately but just deciphering it is not
enough to break the system. The proposed quantum protocol consists of two
stages.

12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
17
The categories of this paper are: q-fin
33
The categories of this paper are: plasm-ph
22
The categories of this paper are: chao-dyn
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat