Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Orthogonal-state-based cryptography in quantum mechanics and local
  post-quantum theories   We introduce the concept of cryptographic reduction, in analogy with a
similar concept in computational complexity theory. In this framework, class
$A$ of crypto-protocols reduces to protocol class $B$ in a scenario $X$, if for
every instance $a$ of $A$, there is an instance $b$ of $B$ and a secure
transformation $X$ that reproduces $a$ given $b$, such that the security of $b$
guarantees the security of $a$. Here we employ this reductive framework to
study the relationship between security in quantum key distribution (QKD) and
quantum secure direct communication (QSDC). We show that replacing the
streaming of independent qubits in a QKD scheme by block encoding and
transmission (permuting the order of particles block by block) of qubits, we
can construct a QSDC scheme. This forms the basis for the \textit{block
reduction} from a QSDC class of protocols to a QKD class of protocols, whereby
if the latter is secure, then so is the former. Conversely, given a secure QSDC
protocol, we can of course construct a secure QKD scheme by transmitting a
random key as the direct message. Then the QKD class of protocols is secure,
assuming the security of the QSDC class which it is built from. We refer to
this method of deduction of security for this class of QKD protocols, as
\textit{key reduction}. Finally, we propose an orthogonal-state-based
deterministic key distribution (KD) protocol which is secure in some local
post-quantum theories. Its security arises neither from geographic splitting of
a code state nor from Heisenberg uncertainty, but from post-measurement
disturbance.

7
The categories of this paper are: hep-th
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th
4
The categories of this paper are: cond-mat
1
The categories of this paper are: cs
3
The categories of this paper are: physics
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat