Reconfigurable free-space quantum cryptography system

• US 10,333,701 B2
• Filed: 02/16/2017
• Issued: 06/25/2019
• Est. Priority Date: 02/29/2016
• Status: Active Grant

• Current Assignee: Board of Trustees of The University of Illinois, Duke University
• Original Assignee: Board of Trustees of The University of Illinois
• Inventors: Kwiat, Paul G., Gauthier, Daniel J.
• Primary Examiner(s): Mehrmanesh, Amir
• Application Number:
  US15/434,313
• Publication Number:
  US 20170250805A1
• Time in Patent Office: 859 Days
• CPC Class Codes: H04B 10/70 Photonic quantum communication
• CPC Class Codes: H04L 9/0822 using key encryption key
• CPC Class Codes: H04L 9/0852 Quantum cryptography transmission systems employing electromagnetic waves other than radio waves, e.g. light, infrared H04B10/00; wavelength-division multiplex systems H04J14/02; WDM arrangements H04J14/03
• CPC Class Codes: H04L 9/0869 involving random numbers or seeds

Abstract

A system, and methods, for transmitting encrypted information as a quantum transmission between a first node and a second node, or among more than two nodes. Each node is characterized by an instantaneous spatial position, and the instantaneous spatial position of the second node is repositionable within a frame of reference associated with the first node. A hovering drone is adapted either for running a quantum key transmission protocol in secure communication with the first node, and/or for running a quantum key reception protocol in secure communication with the second node. Either drone may serve as a relay of optical data between a base station and another drone. Secure communication among more than two nodes may be reconfigured.

Claims

1. A system for transmitting encrypted information comprising:

a first node characterized by a first instantaneous spatial position;

a second node characterized by a second instantaneous spatial position, the second instantaneous spatial position being repositionable within a frame of reference associated with the first node;

a first drone adapted to receive while aloft a secure communication from the first node and further adapted to run a quantum key transmission protocol for transmitting encrypted information as a quantum transmission between the first node and the second node, based on the secure communication from the first node, and to transmit a quantum key to the second node, directly or indirectly via one or more other drones, using the quantum key transmission protocol; and

a second drone adapted to hover aloft in a relative orientation to the first drone so as to maintain alignment of a beam between the first and second drones and wherein the second drone is further adapted to initiate an acquisition protocol to establish quantum key transmission from the first drone to the second drone.

2. A system in accordance with claim 1, wherein the first drone is adapted to receive the secure communication from the first node while in hovering relationship with the first node.

3. A system in accordance with claim 1, wherein the second drone is adapted to run a quantum key reception protocol, based on secure communication with, and in hovering relationship to, the second node.

4. A system in accordance with claim 3, wherein the second drone is adapted to receive a secure communication from the second node while in hovering relationship with the second node.

5. A system in accordance with claim 3, further comprising a locking beacon for maintaining the first and second drone in a relative position for quantum key transmission and reception.

6. A system in accordance with claim 1, wherein the first drone includes a preprogramed source for quantum key distribution.

7. A system in accordance with claim 3, wherein the second drone includes a preprogrammed measurement system for quantum key distribution.

8. A system in accordance with claim 1, wherein the first drone includes a random number generator.

9. A system in accordance with claim 1, further comprising a secure link for transmitting light from a secure source at the first node to the first drone.

10. A system in accordance with claim 1, wherein a random number generator is disposed at the first node.

11. A system in accordance with claim 1, wherein the acquisition protocol employs a finding mechanism chosen from a set of modalities including GPS, inertial guidance, and optical beacons operating at a different wavelength and/or a different temporal mode or a different spatial mode from a wavelength, temporal mode and spatial mode characterizing the quantum transmission.

12. A method for transmitting encrypted information as a quantum signal between a first node and a second node, the method comprising:

sending a first drone aloft in communication with the first node;

receiving at the first drone a secure communication from the first node;

sending a second drone aloft;

initiating an acquisition protocol to establish quantum key transmission from the first to the second drone;

transmitting a quantum key from the first drone to the second node, directly or indirectly via the second drone, using the quantum key transmission protocol;

locking a relative orientation of the first and second drones to maintain alignment of a beam between the first and second drones; and

transmitting data from the first node to the second node via at least the first drone in accordance with a quantum encryption protocol, wherein each node is characterized by an instantaneous spatial position, the instantaneous position of the second node being repositionable within a frame of reference associated with the first node.

13. A method in accordance with claim 12, further comprising transmitting random bits securely from the first node to the first drone.

14. A method in accordance with claim 12, wherein random bits are transmitted securely from the first node to the first drone via an optical fiber tether.

15. A method in accordance with claim 12, wherein random bits are transmitted securely from the first node to the first drone via free-space optics.

16. A method in accordance with claim 12, wherein random bits are generated within the first drone.

17. A method in accordance with claim 12, wherein the first drone is an optical relay of the quantum signal from the first node to the second drone.

18. A method in accordance with claim 12, wherein at least the second drone acts an optical relay of the quantum signal from the first drone to the second node.

19. A method in accordance with claim 12, further comprising performing a QKD measurement aboard the second drone of the quantum signal received by the second drone.

20. A method in accordance with claim 12, further comprising securely transmitting data from the first drone to the second drone.

21. A method in accordance with claim 12, further comprising securely transmitting data among a plurality of drones.