US-12621135-B2 - Method and apparatus for optimizing performance of a quantum key distribution (QKD) protocol

US12621135B2US 12621135 B2US12621135 B2US 12621135B2US-12621135-B2

Abstract

The present disclosure relates to field of quantum cryptography that discloses method of optimizing performance of Quantum Key Distribution (QKD) protocol. Computing system ( 101 ) extracts one or more coincidence distribution sets generated from one or more timestamps detected during communication by one or more detector pairs associated with sender and receiver of communication. Further, computing system identifies one or more reference lines indicating signal value and noise value in each of one or more coincidence distribution sets. Thereafter, computing system determines time window in one or more coincidence distribution sets by iteratively adjusting one or more reference lines in incremental steps until at least one of, performance parameters, signal value and noise value within time window complies with predefined requirements. Finally, computing system optimizes performance of QKD protocol based on determined time window. present disclosure provides an advantage of optimizing individual Signal-to-Noise Ratio (SNR) while restricting QBER to predefined limit.

Inventors

Urbasi SINHA
Sourav Chatterjee

Assignees

RAMAN RESEARCH INSTITUTE

Dates

Publication Date: 20260505
Application Date: 20240520
Priority Date: 20230519

Claims (15)

1 . A method of optimizing performance of a Quantum Key Distribution (QKD) protocol, the method comprising: extracting, by a computing system, one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receiver of the communication, wherein each coincidence distribution set in the one or more coincidence distribution sets comprises a signal coincidence distribution and a noise coincidence distribution; identifying, by the computing system, one or more reference lines indicating signal value and noise value in each of the one or more coincidence distribution sets, wherein the one or more reference lines comprises left reference line and right reference line; determining, by the computing system, a time window in the one or more coincidence distribution sets by iteratively adjusting the one or more reference lines in incremental steps until at least one of, one or more performance parameters, signal value and noise value within the time window complies with one or more predefined requirements; and optimizing, by the computing system, performance of a Quantum Key Distribution (QKD) protocol based on the determined time window.
2 . The method as claimed in claim 1 , wherein optimizing the QKD protocol comprises: identifying, by the computing system, a coincidence distribution set in the one or more coincidence distribution sets with a largest time window, wherein the at least one of, one or more performance parameters, signal value and noise value within the largest time window complies with the one or more predefined requirements; adjusting, by the computing system, a time window in one or more remaining coincidence distribution sets to match the largest time window, wherein the one or more remaining coincidence distribution sets are coincidence distribution sets other than the coincidence distribution set with the largest time window in the one or more coincidence distribution sets; and modifying, by the computing system, the time window of each of the one or more coincidence distribution sets until overall Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets reaches a predefined QBER limit.
3 . The method as claimed in claim 1 , wherein optimizing the QKD protocol comprises: identifying, by the computing system, a coincidence distribution set in the one or more coincidence distribution sets with a largest time window, wherein the at least one of, one or more performance parameters, signal value and noise value within the largest time window complies with the one or more predefined requirements; adjusting, by the computing system, a time window in one or more remaining coincidence distribution sets to match the largest time window, wherein the one or more remaining coincidence distribution sets are coincidence distribution sets other than the coincidence distribution set with the largest time window in the one or more coincidence distribution sets; and modifying, by the computing system, the time window of each of the one or more coincidence distribution sets until individual Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets reaches predefined QBER limit.
4 . The method as claimed in claim 1 , wherein optimizing the QKD protocol comprises: identifying, by the computing system, a coincidence distribution set in the one or more coincidence distribution sets with a maximum Signal to Noise Ratio (SNR) and overall Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets is within a predefined QBER limit; and adjusting, by the computing system, a time window of one or more remaining coincidence distribution sets to the one or more reference lines, wherein the process of identifying the coincidence distribution set in the one or more coincidence distribution sets is performed in the one or more remaining coincidence distribution sets until the QBER reaches the predefined QBER limit and overall key symmetry of the signal is within a predefined key symmetry.
5 . The method as claimed in claim 1 , wherein the one or more predefined requirements comprises obtaining maximum Signal to Noise Ratio (SNR) and Quantum Bit Error Rate (QBER) of the determined time window is within a predefined QBER limit.
6 . The method as claimed in claim 1 , wherein determining the time window in the one or more coincidence distribution sets comprises adjusting the left reference line and right reference line in equal incremental steps.
7 . The method as claimed in claim 6 , wherein adjusting the one or more reference lines comprises varying the time delays by a predefined value.
8 . A computing system for optimizing performance of a Quantum Key Distribution (QKD) protocol, the computing system comprising: a processor; and a memory, communicatively coupled to the processor, wherein the memory stores processor executable instructions, which, on execution, causes the processor to: extract one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receiver of the communication, wherein each coincidence distribution set in the one or more coincidence distribution sets comprises a signal coincidence distribution and a noise coincidence distribution; identify one or more reference lines indicating signal value and noise value in each of the one or more coincidence distribution sets, wherein the one or more reference lines comprises left reference line and right reference line; determine a time window in the one or more coincidence distribution sets by iteratively adjusting the one or more reference lines in incremental steps until at least one of, one or more performance parameters, signal value and noise value within the time window complies with one or more predefined requirements; and optimize performance of a Quantum Key Distribution (QKD) protocol based on the determined time window.
9 . The computing system as claimed in claim 8 , wherein to optimize the QKD protocol the processor is configured to: identify a coincidence distribution set in the one or more coincidence distribution sets with a largest time window, wherein the at least one of, one or more performance parameters, signal value and noise value within the largest time window complies with the one or more predefined requirements; adjust a time window in one or more remaining coincidence distribution sets to match the largest time window, wherein the one or more remaining coincidence distribution sets are coincidence distribution sets other than the coincidence distribution set with the largest time window in the one or more coincidence distribution sets; and modify the time window of each of the one or more coincidence distribution sets until overall Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets reaches a predefined QBER limit.
10 . The computing system as claimed in claim 8 , wherein to optimize the QKD protocol the processor is configured to: identify a coincidence distribution set in the one or more coincidence distribution sets with a largest time window, wherein the at least one of, one or more performance parameters, signal value and noise value within the largest time window complies with the one or more predefined requirements; adjust a time window in one or more remaining coincidence distribution sets to match the largest time window, wherein the one or more remaining coincidence distribution sets are coincidence distribution sets other than the coincidence distribution set with the largest time window in the one or more coincidence distribution sets; and modify the time window of each of the one or more coincidence distribution sets until individual Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets reaches predefined QBER limit.
11 . The computing system as claimed in claim 8 , wherein to optimize the QKD protocol the processor is configured to: identify a coincidence distribution set in the one or more coincidence distribution sets with a maximum Signal to Noise Ratio (SNR) and overall Quantum Bit Error Rate (QBER) of the one or more coincidence distribution sets is within a predefined QBER limit; and adjust a time window of one or more remaining coincidence distribution sets to the one or more reference lines, wherein the process of identifying the coincidence distribution set in the one or more coincidence distribution sets is performed in the one or more remaining coincidence distribution sets until the QBER reaches the predefined QBER limit and overall key symmetry of the signal is within a predefined key symmetry.
12 . The computing system as claimed in claim 8 , wherein the one or more predefined requirements comprises obtaining maximum Signal to Noise Ratio (SNR) and Quantum Bit Error Rate (QBER) of the determined time window is within a predefined QBER limit.
13 . The computing system as claimed in claim 8 , wherein to determine the time window in the one or more coincidence distribution sets, the processor is configured to adjust the left reference line and right reference line in equal incremental steps.
14 . The computing system as claimed in claim 13 , wherein adjusting the one or more reference lines comprises varying the time delays by a predefined value.
15 . A non-transitory computer readable medium including instructions stored thereon that when processed by at least one processor, cause a computing system to perform operations comprising: extracting one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receiver of the communication, wherein each coincidence distribution set in the one or more coincidence distribution sets comprises a signal coincidence distribution and a noise coincidence distribution; identifying one or more reference lines indicating signal value and noise value in each of the one or more coincidence distribution sets, wherein the one or more reference lines comprises left reference line and right reference line; determining a time window in the one or more coincidence distribution sets by iteratively adjusting the one or more reference lines in incremental steps until at least one of, one or more performance parameters, signal value and noise value within the time window complies with one or more predefined requirements; and optimizing performance of a Quantum Key Distribution (QKD) protocol based on the determined time window.

Description

TECHNICAL FIELD The present disclosure relates, in general, to quantum cryptography. Particularly, the present disclosure relates to a method and apparatus for optimizing performance of a Quantum Key Distribution (QKD) protocol. BACKGROUND Quantum Key Distribution (QKD) is a most rapidly developing technology of quantum cryptography. QKD protocol is utilized for providing a secure communication between a sender and a receiver. The QKD enables the sender and the receiver to securely communicate with each other by establishing a secret key string. In the QKD protocol, the parties can perform communication while maintaining the information-theoretically secure by encrypting messages using a one-time pad symmetric key algorithm. Further, in the QKD protocol, the security is guaranteed by the fundamental laws of quantum mechanics. Thus, detecting any eavesdropping activity. The conventional technologies of assessing the performance of any QKD protocol generally include unoptimized data-analyses, where the two parties trying to establish a secret key string pre-agree upon a fixed coincidence window span and calculate the extractable key rate, the Quantum-Bit-Error-Rate (QBER), and the key symmetry within the fixed coincidence window span. However, by fixing a pre-agreed coincidence window span, without optimizing it, may often limit the scope of offering maximal key rate against minimal QBER for a particular protocol demonstration. Therefore, there is a need for a system to determine the coincidence window span dynamically that in turn is capable of offering maximal key rate against the minimal QBER. The information disclosed in this background of the disclosure section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. SUMMARY Disclosed herein is a method of optimizing performance of a Quantum Key Distribution (QKD) protocol. The method of extracting, by a computing system, one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receiver of the communication. Each coincidence distribution set in the one or more coincidence distribution sets comprises a signal coincidence distribution and a noise coincidence distribution. Further, the method comprises identifying one or more reference lines indicating signal value and noise value in each of the one or more coincidence distribution sets. The one or more reference lines comprises left reference line and right reference line. Thereafter, the method comprises determining a time window in the one or more coincidence distribution sets by iteratively adjusting the one or more reference lines in incremental steps until at least one of, one or more performance parameters, signal value and noise value within the time window complies with one or more predefined requirements. Finally, the method comprises optimizing performance of a QKD protocol based on the determined time window. Further, the present disclosure relates to a computing system for optimizing performance of a Quantum Key Distribution (QKD) protocol. The computing system comprises a processor and a memory. The memory is communicatively coupled to the processor and stores processor-executable instructions, which on execution, cause the processor to extract one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receiver of the communication. Each coincidence distribution set in the one or more coincidence distribution sets comprises a signal coincidence distribution and a noise coincidence distribution. Further, the processor identifies one or more reference lines indicating signal value and noise value in each of the one or more coincidence distribution sets. The one or more reference lines comprises left reference line and right reference line. Thereafter, the processor determines a time window in the one or more coincidence distribution sets by iteratively adjusting the one or more reference lines in incremental steps until at least one of, one or more performance parameters, signal value and noise value within the time window complies with one or more predefined requirements. Finally, the processor optimizes performance of a QKD protocol based on the determined time window. Furthermore, the present disclosure relates to a non-transitory computer readable medium including instructions stored thereon that when processed by at least one processor, cause a computing system to perform operations comprising extracting one or more coincidence distribution sets generated from one or more timestamps detected during a communication by one or more detector pairs associated with a sender and a receive