Smart Home Key Exchange for Offline Device Sharing

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Solution Overview

Problem

Existing smart home technologies cannot facilitate offline sharing of home devices, as public key exchange requires all devices involved to be online, limiting control and management capabilities when devices are offline.

Innovation Solution

A method where a first device shares a home device with a second device by obtaining and encrypting public keys using message leaving keys, allowing for offline communication and control, even if either the home device or the second device is offline, through a server-mediated encryption process that ensures user information security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If public key exchange is performed through online communication between sharing client, acceptance client, and home device, then signature verification can be completed, but offline sharing cannot be achieved

Engineering Contradiction:
Improvesignature verification reliabilityVSAvoidoffline sharing capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies preliminary action by having the sharing client obtain the acceptance client's public key in advance through the server before actual sharing occurs. This pre-obtained public key is stored locally, enabling the sharing client to perform signature verification on offline messages without requiring the acceptance client to be online, thus resolving the contradiction between reliable verification and offline capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces the server as an intermediary to facilitate public key distribution. The server mediates between the acceptance client and sharing client by providing the public key to the sharing client, enabling offline sharing while maintaining security through the intermediary's trusted distribution mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If all devices must be online simultaneously for public key exchange, then secure communication can be established, but user convenience deteriorates

Engineering Contradiction:
Improvecommunication securityVSAvoidsharing operation convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The sharing client performs preliminary action by obtaining and storing the acceptance client's public key in advance through server-mediated communication. This preliminary key acquisition eliminates the need for simultaneous online presence during actual sharing operations, maintaining security while dramatically improving ease of operation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent extracts the public key from the acceptance client through the server and stores it locally in the sharing client. This extraction separates the key acquisition phase from the sharing execution phase, allowing secure communication to be established beforehand and enabling convenient offline sharing operations

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If public keys are exchanged through direct device communication, then communication efficiency is maintained, but offline sharing capability is lost

Engineering Contradiction:
Improvekey exchange efficiencyVSAvoidoffline message handling
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The server acts as an intermediary that efficiently distributes public keys to sharing clients in advance. This intermediary mechanism maintains key exchange efficiency through automated server-mediated distribution while enabling offline sharing capability, as the sharing client already possesses the necessary public key for verifying offline messages from the acceptance client

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4050838B1Device sharing method and electronic device
Publication Date: 2023.12.20 HUAWEI TECH CO LTD
  • EP4050838B1 patent drawingFigure 1
  • EP4050838B1 patent drawingFigure 2
  • EP4050838B1 patent drawingFigure 3A

AI summary

This application provides a device sharing method and an electronic device. The device sharing method and the electronic device relate to the field of communications technologies and the field of smart home technologies, and can implement offline sharing of a first home device. The solution includes: A first device obtains a public key of a first home device and a first message leaving key that is used to encrypt an offline message between the first device and the first home device; obtains a public key of a second device and a second message leaving key that is used to encrypt an offline message between the first device and the second device; obtains a third message leaving key used to encrypt an offline message between the second device and the first home device; encrypts the public key of the second device and the third message leaving key by using the first message leaving key, to obtain first encrypted information, and requests a server to push the first encrypted information to the first home device; and encrypts the public key of the first home device and the third message leaving key by using the second message leaving key, to obtain second encrypted information, and requests the server to push the second encrypted information to the second device.