Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced secure key exchange systems based on the Johnson-noise scheme   We introduce seven new versions of the Kirchhoff-Law-Johnson-(like)-Noise
(KLJN) classical physical secure key exchange scheme and a new transient
protocol for practically-perfect security. While these practical improvements
offer progressively enhanced security and/or speed for the non-ideal
conditions, the fundamental physical laws providing the security remain the
same.
  In the "intelligent" KLJN (iKLJN) scheme, Alice and Bob utilize the fact that
they exactly know not only their own resistor value but also the stochastic
time function of their own noise, which they generate before feeding it into
the loop.
  In the "multiple" KLJN (MKLJN) system, Alice and Bob have publicly known
identical sets of different resistors with a proper, publicly known truth table
about the bit-interpretation of their combination. In the "keyed" KLJN (KKLJN)
system, by using secure communication with a formerly shared key, Alice and Bob
share a proper time-dependent truth table for the bit-interpretation of the
resistor situation for each secure bit exchange step during generating the next
key.
  The remaining four KLJN schemes are the combinations of the above protocols
to synergically enhance the security properties. These are: the
"intelligent-multiple" (iMKLJN), the "intelligent-keyed" (iKKLJN), the
"keyed-multiple" (KMKLJN) and the "intelligent-keyed-multiple" (iKMKLJN) KLJN
key exchange systems.
  Finally, we introduce a new transient-protocol offering practically-perfect
security without privacy amplification, which is not needed at practical
applications but it is shown for the sake of ongoing discussions.

32
The categories of this paper are: atom-ph
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
10
The categories of this paper are: q-bio
0
The categories of this paper are: hep-ph
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn