Encryption Key Generation via Bidirectional QKD Load Balancing

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Solution Overview

Problem

In data transmission systems, particularly quantum key distribution (QKD), significant data loss occurs, leading to inefficient processing due to unbalanced data volumes and increased processing loads between transmission and reception ends.

Innovation Solution

Implementing a pair of transmission systems with opposite directions to distribute the processing load by allowing partial data reception in each direction, enabling equalization of processing loads through identical information processing in both communication devices.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If quantum key distribution transmits random numbers through quantum channels, then secure key generation is achieved, but most transmitted data is lost due to transmission line loss

Engineering Contradiction:

ImprovesecurityVSAvoiddata loss

Core Design Contradiction:

ReliabilityVSLoss of information

Solution Approach 1:

The system segments the data processing task by separating transmitted data from received data, allowing each communication device to process only the data it actually receives rather than attempting to process all transmitted data, thereby reducing processing load while maintaining security

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of the transmission end processing all transmitted data and the reception end processing only received data, the invention inverts this by having both ends process only their respective received data, equalizing the processing burden

Inventive Principle:

Principle #13The other way round (Inversion)

2Productivity

If basis reconciliation, error correction, and privacy amplification processing are performed on raw key, then encryption key generation is achieved, but processing load becomes unbalanced between transmission end and receiving end

Engineering Contradiction:

Improveencryption key generationVSAvoidprocessing load distribution

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The processing operations (basis reconciliation, error correction, privacy amplification) are segmented and executed locally at each communication device on the data it receives, rather than centralizing processing at one end, thereby distributing the computational burden

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The traditional asymmetric processing model where one end handles all processing is inverted to a symmetric model where both ends perform identical processing operations on their respective received data, achieving load equalization

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If data elimination is performed in subsequent processes, then security against wiretapping is improved, but received data volume becomes very small compared with transmitted data volume

Engineering Contradiction:

ImprovesecurityVSAvoiddata volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

Each communication device performs data processing only on the partial data it actually receives rather than attempting to process all transmitted data, which is both sufficient for security and reduces unnecessary processing on non-existent data

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS12407613B2Encryption key generation

Publication Date: 2025.09.02 NEC CORP

AI summary

A first device transmits a first random number to a second device through a first quantum channel, and receives a second random number from the second device through a second quantum channel. The first device generates a first encryption key based on the first random number and the second random number. The second device transmits the second random number to the first device through the second quantum channel, and receives the first random number from the first device through the first quantum channel. The second device generates a second encryption key based on the first random number and the second random number.