Quantum Key Distribution Using Feedback Error Correction

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current quantum key distribution methods face challenges in achieving secure encryption with shorter key lengths while maintaining information transmission efficiency, particularly when using quantum correlations, which can violate the principle of information causality.

Innovation Solution

The method involves generating and reconciling quantum signals using initial keys in data processing devices, employing quantum measurement parameters to create encrypted signals, and correcting these signals to determine shared keys, which can be shorter than the original message while ensuring security through encryption and error correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If quantum correlations are used to violate information causality, then key length can be reduced, but security may be compromised

Engineering Contradiction:
Improvekey lengthVSAvoidsecurity
Core Design Contradiction:
Loss of informationVSReliability

Solution Approach 1:

The patent implements feedback through error correction protocols where measurement results are communicated back between parties to reconcile differences and establish identical keys. This feedback mechanism ensures security by detecting and correcting errors that could compromise the key, while still allowing shorter keys to be used effectively.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent introduces intermediary classical communication channels that mediate between the quantum correlation generation and the final key establishment. This intermediary layer allows for verification and error correction, ensuring security while enabling the use of shorter quantum keys than would be possible with purely classical methods.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If key length is reduced for efficient encryption, then information transmission efficiency improves, but the amount of secure information that can be transmitted decreases

Engineering Contradiction:
Improveinformation transmission efficiencyVSAvoidinformation transmission capacity
Core Design Contradiction:
ProductivityVSLoss of information

Solution Approach 1:

The patent segments the key distribution process into distinct phases: quantum correlation generation, classical error correction, and final key establishment. This segmentation allows each phase to be optimized independently, achieving high transmission efficiency in the quantum phase while ensuring sufficient key length through the classical reconciliation phase.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-dimension classical key distribution to a multi-dimensional approach combining quantum states with multiple measurement bases. This dimensional expansion allows for more information to be encoded in shorter keys through the use of quantum superposition and entanglement, thereby increasing transmission capacity without proportionally increasing key length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Productivity

If more quantum measurement parameters are used, then key rate increases, but device complexity increases

Engineering Contradiction:
Improvekey rateVSAvoidmeasurement system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements universal measurement devices that can perform multiple types of quantum measurements on the same hardware platform. This multi-functionality allows for increased key rates by utilizing different measurement bases and parameters without requiring separate dedicated devices for each measurement type, thereby avoiding proportional increases in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enhances the key rate and reduces information leakage to eavesdroppers, allowing for more efficient and secure data transmission by minimizing the amount of data accessible to outside devices, thereby increasing the key length without increasing the initial key data.

Implementation Method 1

determining a raw signal by quantum measuring the plurality of quantum states employing the plurality of quantum measurement parameters

Methodology Applied
Scientific EffectQuantum measurement:

Implementation Method 2

generating with the initial key in the second data processing device, an encrypted signal indicating at least one the plurality of quantum measurement parameters and transmitting the encrypted signal to the first data processing device

Methodology Applied
Scientific EffectSignal transmission:

Implementation Method 3

determining a shared key from the reconciled signal by correcting the reconciled signal

Methodology Applied
Scientific EffectError correction:

Data Source

PatentEP4037247B1Method and system for quantum key distribution
Publication Date: 2024.06.19 TERRA QUANTUM AG
  • EP4037247B1 patent drawingFigure 1
  • EP4037247B1 patent drawingFigure 2
  • EP4037247B1 patent drawingFigure 3a)~3b)

AI summary

A method for quantum key distribution in a system comprising a plurality of data processing devices comprises: providing an initial key in a first data processing device and a second data processing device; providing, in the second data processing device, a quantum signal comprising a plurality of quantum states; determining, in the second data processing device, a plurality of quantum measurement parameters; determining, in the second data processing device, a raw signal by quantum measuring the plurality of quantum states employing the plurality of quantum measurement parameters; generating with the initial key, in the second data processing device, an encrypted signal indicating at least one the plurality of quantum measurement parameters and transmitting the encrypted signal to the first data processing device; determining, in at least one of the first data processing device and the second data processing device, a reconciled signal from the encrypted signal; determining, in at least one of the first data processing device and the second data processing device, a shared key from the reconciled signal by correcting the first reconciled signal.