Encrypted Messaging Device Verification via QR Code Credential Exchange
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Solution Overview
Problem
Existing messaging systems face challenges in securely authorizing secondary devices to send and receive encrypted messages on behalf of a user without sharing private encryption keys, and in managing device lists to ensure secure communication and prevent unauthorized access.
Innovation Solution
A method where a primary device verifies a secondary device by exchanging computer-perceptible codes, such as QR codes, to generate cryptographic credentials, and maintains a list of authorized devices, with the server facilitating communication without verifying device lists, ensuring only the primary device can add new devices, and participants verify signatures to confirm authorized devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary device verifies a secondary device by exchanging computer-perceptible codes to generate cryptographic credentials, then secure authorization of secondary devices is achieved without sharing private keys, but the device complexity and verification process time increase
Solution Approach 1:
A server acts as an intermediary to facilitate the verification process between primary and secondary devices. The server receives verification requests, manages the exchange of cryptographic credentials, and coordinates the addition of secondary devices to the approved device list, reducing the direct complexity between end devices
Solution Approach 2:
The system uses public key cryptography where the primary device receives a copy of the secondary device's public key through computer-perceptible codes. This allows verification without sharing private keys, achieving secure authorization while managing complexity through asymmetric cryptography
2Productivity
If the server facilitates communication without verifying device lists, then communication efficiency is improved, but security control and unauthorized access prevention worsen
Solution Approach 1:
The primary device performs preliminary verification of secondary devices before adding them to the approved device list. This pre-verification ensures security control is maintained at the client level while the server can focus on efficient message routing without redundant verification steps
Solution Approach 2:
Security responsibilities are segmented between the primary device (which verifies and manages the approved device list) and the server (which facilitates communication). This division allows the server to maintain high communication efficiency while the primary device ensures security control
3Object-affected harmful factors
If participants verify signatures to confirm authorized devices, then unauthorized access prevention is improved, but the verification time and processing overhead increase
Solution Approach 1:
The system uses digital signatures where the primary device signs the approved device list with its private key. Participants verify these signatures using the primary device's public key, which provides strong unauthorized access prevention while being computationally efficient compared to alternative verification methods
Data Source
AI summary
This application describes methods, mediums, and systems for verifying a device for use in a messaging system. Using the device verification procedures described, a messaging system can securely authorize new devices to send and receive encrypted messages on behalf of a user, preferably without the need to share a private encryption key between the users' different devices. The application describes several techniques that can be used to provide such a system, including distributing a computer-perceptible code that encodes encryption information between a secondary device and a primary device. This allows the information to be distributed without intervention by a server. Other techniques provide unique ways to build and reverify authorized device lists, distribute encryption keys in chat channels, ensure that lists of authorized devices are distributed in the correct order and remain valid for an appropriate amount of time, add new devices to an ongoing or new conversation, and more.