US 11,818,258 B2
Method and system for quantum key distribution
Gordey Lesovik, St. Gallen (CH); Dmitry Kronberg, St. Gallen (CH); Alexey Kodukhov, Rorschach (CH); Valeria Pastushenko, St. Gallen (CH); Nurbolat Kenbayev, St. Gallen (CH); Nikita Kirsanov, St. Gallen (CH); Pavel Sekatski, St. Gallen (CH); Valerii Vinokour, St. Gallen (CH); and Asel Sagingalieva, St. Gallen (CH)
Assigned to Terra Quantum AG, St. Gallen (CH)
Filed by Terra Quantum AG, St. Gallen (CH)
Filed on Feb. 18, 2022, as Appl. No. 17/675,570.
Claims priority of application No. 21157942 (EP), filed on Feb. 18, 2021; application No. 21166427 (EP), filed on Mar. 31, 2021; and application No. 21168449 (EP), filed on Apr. 14, 2021.
Prior Publication US 2022/0271928 A1, Aug. 25, 2022
Int. Cl. H04L 29/06 (2006.01); H04L 9/08 (2006.01); G06N 10/20 (2022.01)
CPC H04L 9/0858 (2013.01) [G06N 10/20 (2022.01); H04L 9/0838 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method for quantum key distribution, the method being implementable in a system with a plurality of data processing devices, the method comprising:
determining, in at least one of a first data processing device and a second data processing device, an intrinsic loss along a quantum channel between the first data processing device and the second data processing device;
generating, in the first data processing device, a first signal;
generating, in the first data processing device, a pulse sequence comprising at least one test pulse and signal pulses generated from the first signal;
transmitting the pulse sequence from the first data processing device via the quantum channel to the second data processing device;
receiving the pulse sequence in the second data processing device, and
determining, in the second data processing device, a second signal from the pulse sequence;
determining invalid signal positions and providing the invalid signal positions in the first data processing device and the second data processing device;
determining, in the first data processing device, a first reconciled signal from the first signal and the invalid signal positions and determining, in the second data processing device, a second reconciled signal from the second signal and the invalid signal positions;
determining a total loss along the quantum channel from the at least one test pulse received in the second data processing device, determining a signal loss from the total loss and the intrinsic loss, and providing the signal loss in the first and the second data processing device;
determining a shared key in the first and the second data processing device by error correcting the first reconciled signal in the first data processing device and error correcting the second reconciled signal in the second data processing device; and
determining an amplified key in the first and the second data processing device from the shared key by shortening the shared key by a shortening amount that is determined from the signal loss.