Quantum Share Distribution for Uneven QKD Key Rates

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Solution Overview

Problem

Existing quantum cryptography storage systems face inefficiencies due to differences in quantum key sharing rates between node pairs, leading to slower transmission times and incomplete distributed storage processing when using one-time pad encryption with quantum keys.

Innovation Solution

A quantum cryptography storage system that determines a distribution mode of shares based on the available quantum key sharing rates between nodes, adjusting the size and number of shares to ensure balanced transmission times across all node pairs, thereby ensuring information-theoretic security and completing distributed storage more efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If one-time pad encryption with quantum keys is used for distributed storage, then information-theoretic security is ensured, but transmission time increases due to differences in quantum key sharing rates between node pairs

Engineering Contradiction:
Improveinformation-theoretic securityVSAvoidtransmission time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent dynamically adjusts share sizes based on quantum key sharing rates between node pairs. By changing the parameter of share size according to the key sharing rate, the system optimizes transmission time while maintaining security. Nodes with higher key sharing rates receive larger shares, while nodes with lower rates receive smaller shares, balancing the overall distributed storage completion time.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If fixed share sizes are used in distributed storage, then simplicity is maintained, but transmission efficiency decreases when quantum key sharing rates vary between node pairs

Engineering Contradiction:
Improvedistribution mode simplicityVSAvoiddistributed storage efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements a dynamic distribution mode where share sizes are not fixed but are determined based on real-time quantum key sharing rates. The distribution control device calculates optimal share sizes for each node pair according to their key sharing capabilities, making the system adaptive to varying network conditions and key generation rates, thereby improving overall distributed storage efficiency.

Inventive Principle:
Principle #15Dynamics

3Reliability

If quantum keys are generated and shared between all node pairs, then security is maximized, but key generation overhead and system complexity increase

Engineering Contradiction:
Improvesecurity levelVSAvoidkey management complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the key management process by establishing quantum key sharing relationships only between the distribution control device and individual shareholders, rather than requiring all-pair key sharing. This segmentation reduces the number of key management relationships from O(n²) to O(n), significantly lowering system complexity while maintaining security through the centralized control device that coordinates share distribution.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4181458B1Quantum cryptography storage system, distribution control device, and computer-readable medium
Publication Date: 2026.03.04 KK TOSHIBA
  • EP4181458B1 patent drawingFigure 1
  • EP4181458B1 patent drawingFigure 2
  • EP4181458B1 patent drawingFigure 3A~3B

AI summary

According to an arrangement, a quantum cryptography storage system (100) includes a plurality of storage devices (3), a distribution control device (4), and a distribution device. The plurality of storage devices (3) are connected via a communication network. The distribution control device (4) determines a distribution mode of shares into which data is distributed, based on quantum key distribution network (QKDN) information. The generation device generates an encryption key and a decryption key by using a quantum key shared by using a QKDN. The distribution device distributes the data into the shares, based on the distribution mode. When receiving a share encrypted using the encryption key via the communication network, each of the plurality of storage devices (3) that stores the shares in a distributed manner decrypts the share encrypted with the decryption key and stores a share decrypted.