One-Way Key Switching for Secure Communication Networks

Solution Overview

Problem

Existing key update mechanisms in communication networks fail to ensure that receivers can correctly switch between the original and new keys, leading to potential data protection issues when the new key is not properly obtained by all receivers, resulting in inability to de-protect data.

Innovation Solution

A one-way key switching method where the sender sets the new key as unavailable until it is deduced that all receivers have obtained it, then switches to using the new key, while the receiver sets both keys as available initially and switches to only the new key after successful de-protection with it, ensuring data can be de-protected using either key.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the sender switches to the new key immediately after receiving it, then the key update speed is improved, but the receiver may be unable to de-protect data because it hasn't received or processed the new key yet

Engineering Contradiction:

Improvekey update speedVSAvoiddata de-protection reliability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The receiver performs preliminary action by pre-processing and storing the new key before the sender actually switches to it. The receiver receives the new key in advance, validates it, and prepares it for use, ensuring that when the sender switches keys, the receiver is already ready to de-protect data with the new key, thus preventing data loss during key transition

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanism where the receiver sends acknowledgment to the sender about key reception status. The sender monitors whether the receiver has successfully received and processed the new key, and only switches keys when confirmation is received, ensuring synchronized key transitions between sender and receiver

Inventive Principle:

Principle #23Feedback

2Reliability

If the sender waits for the receiver to process the new key before switching, then data de-protection reliability is improved, but the key update speed deteriorates

Engineering Contradiction:

Improvedata de-protection reliabilityVSAvoidkey update speed

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The receiver performs preliminary action by pre-processing and storing the new key before the sender actually switches to it. The receiver receives the new key in advance, validates it, and prepares it for use, ensuring that when the sender switches keys, the receiver is already ready to de-protect data with the new key, thus preventing data loss during key transition

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanism where the receiver sends acknowledgment to the sender about key reception status. The sender monitors whether the receiver has successfully received and processed the new key, and only switches keys when confirmation is received, ensuring synchronized key transitions between sender and receiver

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If both sender and receiver switch keys at different time instants, then operational flexibility is improved, but the risk of communication failure increases

Engineering Contradiction:

Improvekey switching flexibilityVSAvoidcommunication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies asymmetry by allowing the receiver to switch keys earlier than the sender. The receiver is permitted to adopt the new key before the sender completes its switch, creating an asymmetric key switching timeline. This is compensated by the sender's side which maintains compatibility with both old and new keys during the transition period, ensuring that data can be de-protected regardless of which key the sender used

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system provides beforehand cushioning by having the receiver prepare and store multiple keys (both old and new) before the actual key switching occurs. This cushioning buffer of pre-loaded keys ensures that even if timing is not perfectly synchronized, the receiver will always have the appropriate key available to de-protect incoming data, preventing communication failures during the transition period

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS9705671B2One-way key switching method and implementation device

Publication Date: 2017.07.11 CHINA IWNCOMM

AI summary

A one-way key switching method and an implementation device. The method comprises: after obtaining a new key and before deducing or determining that at least n receivers obtain the new key, a sender setting the sending direction of the new key as unavailable and keeping the sending direction of an original key as available; after obtaining the new key and before deducing or determining that at least n receivers obtain the new key, before the original key is invalid, the sender starting up a key switching process, i.e. setting the sending direction of the original key as unavailable and setting the sending direction of the new key as available; where N≧n≧1, N is the total number of the receivers corresponding to the sender.