Wireless Device Encryption Key Change Timing

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Solution Overview

Problem

Existing wireless communication systems for cordless telephones, such as those using the DECT scheme, face challenges in maintaining secure encryption communication during calls, particularly in managing encryption keys effectively to prevent communication quality degradation and discontinuance due to reception errors.

Innovation Solution

A wireless communications device that evaluates communication quality and changes encryption keys only when the quality is good, using a timer to determine when to initiate a new encryption key, thereby reducing the frequency of reception errors and noise during key changes, and allowing for secure and continuous communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If encryption key changes are performed frequently during calls, then security performance is improved, but communication quality degrades due to reception errors and noise

Engineering Contradiction:
Improvesecurity performanceVSAvoidreception errors and noise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic key change timing based on communication quality assessment. Instead of fixed periodic key changes, the system evaluates communication quality indicators (such as signal strength, error rates) and adjusts the key change timing accordingly. When quality is good, key changes proceed as scheduled; when quality deteriorates, key changes are delayed or cancelled, thus adapting the security mechanism to current communication conditions and avoiding degradation from poor-quality transmissions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system incorporates feedback mechanisms by continuously monitoring communication quality metrics and using this information to control the encryption key change process. The quality assessment feedback determines whether to proceed with or postpone key changes, creating a closed-loop control system that balances security requirements with communication reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If encryption key changes are initiated, then security is maintained, but communication discontinuance occurs due to reception errors during key change

Engineering Contradiction:
Improveencryption securityVSAvoidcommunication continuity
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent performs preliminary assessment of communication quality before initiating encryption key changes. By evaluating communication conditions in advance and only proceeding with key changes when quality thresholds are met, the system prevents key change operations that would likely fail due to poor reception, thereby avoiding communication discontinuance while maintaining security through timely key changes under favorable conditions.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If automatic key generation and storage is implemented, then convenience is improved, but key management complexity increases

Engineering Contradiction:
Improvekey management convenienceVSAvoidkey management system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The system implements self-service key management by automatically generating, storing, and managing encryption keys without user intervention. The device autonomously handles key generation using secure algorithms, stores keys in protected memory, and manages key lifecycle including rotation and replacement, thereby providing convenience to users while encapsulating the complexity within the device's automated key management infrastructure.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP3128694B1Wireless communications device and control method for wireless communications device
Publication Date: 2020.12.09 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP3128694B1 patent drawingFigure 1~2
  • EP3128694B1 patent drawingFigure 3
  • EP3128694B1 patent drawingFigure 4

AI summary

A wireless communications device, that is constituted from a control station and a slave station that perform encryption communication using an encryption key, includes a controller that monitors communication quality of a state of a call to the slave station and, in a case where the communication quality degrades to below the same level as a state that is determined in advance, operates in such a manner that a procedure for changing the encryption key, which is determined in advance, is not activated.