US 12,640,819 B2Granted

Apparatus and method for secure space communication

AssigneesUniversite De Geneve, Universitat Auonoma De Barcelona

InventorsHugo Zbinden, Angeles Vazquez Castro

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Abstract

Free-Space quantum keyless private communication method according to a communication protocol comprising exchanging information between an emitter (100) and a receiver (200) through a main quantum-classical channel and with an eavesdropper tapping said main channel through a wiretap channel, based on the wiretap channel model, wherein the overall degradation of the wiretap channel is superior than that of the main channel, comprising the steps of preparing, at the emitter (100), a message M composed of classical bits, coding said message M so as to transform it into a coded message X, practical modulating the amplitude and/or the phase of the optical pulses of the coded classical bits, sending the encoded message to the receiver (200) through a classical-quantum channel (500), such that an eavesdropper (300) tapping said channel is provided with partial information about the said states only, detecting and decoding the received message through quantum security analysis.

Claims16

Dependent claims

defining an exclusion radius re surrounding the receiver (200) and computing a degradation parameter γ based on said exclusion radius re wherein the degradation parameter γ permits that the overall degradation of the wiretap channel is superior to that of the main channel and a wiretap channel degrading step based on the degradation parameter,
preparing, at the emitter (100), a message M composed of classical bits,
coding said message M so as to transform it into a coded message X,
converting the classical bits of the coded message into a signal to be sent to Bob by modulating an amplitude and/or a phase of coherent states,
sending the signal comprising the coded message to the receiver (200) through a quantum-classical channel (500), such that an eavesdropper (300) tapping said channel is provided with partial information about the said states only, and
detecting and decoding the received message.

3 more elements

calculating a degradation parameter γ depending on a receiver's parameter, such that
γ
⁡
(
d
B
,
d
E
,
η
b
,
θ
E
,
θ
div
)
=
1
η
b
⁢
(
d
B
d
E
)
2
⁢
(
D
R
E
D
R
B
)
2
⁢
e
-
2
⁢
(
2
⁢
θ
E
θ
div
)
2
where dB is a distance between the emitter and the receiver, dE is the Distance Between the emitter and the eavesdropper, DER is a diameter of the of an antenna of the eavesdropper, DBR is a diameter of the antenna of the receiver, ηB is a (additional) loss of the receiver, θdiv is a far field divergence, and θE is Eve's angle to a satellite;
defining an exclusion surrounding the receiver (200) based on the degradation parameter γ;
preparing, at the emitter (100), a message M composed of classical bits;
coding said message M so as to transform it into a coded message X;
converting the classical bits of the coded message into a signal to be sent to Bob by modulating an amplitude and/or a phase of the coherent states;
sending the signal comprising the encoded message to the receiver (200) through a quantum-classical channel (500), such that an eavesdropper (300) tapping said channel is provided with partial information about the said states only;
and
detecting and decoding the received message.

60 more elements

Dependencies are inferred from the claim text.