Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: High-density and Secure Data Transmission via Linear Combinations   Suppose that there are $n$ Senders and $n$ Receivers. Our goal is to send
long messages from Sender $i$ to Receiver $i$ such that no other receiver can
retrieve the message intended for Receiver $i$. The task can easily be
completed using $n$ private channels between the pairs. Solutions, using one
channel needs either encryption or switching elements for routing the messages
to their addressee.
  The main result of the present work is a description of a network in which
The Senders and the Receivers are connected with only $n^{o(1)}$ channels; the
encoding and de-coding is nothing else just very fast linear combinations of
the message-bits; and there are no switching or routing-elements in the
network, just linear combinations are computed, with fixed connections
(channels or wires).
  In the proofs we do not use {\em any} unproven cryptographical or complexity
theoretical assumptions.

8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
4
The categories of this paper are: cond-mat
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys
3
The categories of this paper are: physics
26
The categories of this paper are: bayes-an
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph