Message Signing with Segmented Digital Signatures
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Solution Overview
Problem
Conventional messaging systems face challenges in providing complete authentication and integrity when a message is forwarded or replied to, as the communication device may sign a message that has been altered by a server, leading to incomplete authentication.
Innovation Solution
A method and system for signing messages that involve combining portions of a message, one from the communication device and one from the server, and generating digital signatures for both portions to ensure authentication and integrity, with the server obtaining a second signature for the complete message and sending it to the destination along with the first signature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the server adds text or attachments to the message, then the message is enhanced with additional content, but the authentication completeness deteriorates because the communication device signs a message that has been subsequently changed
Solution Approach 1:
The message is divided into two portions: the first portion (original message from communication device) and the second portion (added content from server). Each portion is signed separately with different digital signatures, allowing independent verification of authentication and integrity for each segment.
Solution Approach 2:
The first digital signature and first portion are nested within the complete message that includes the second portion. The server generates a second digital signature for the complete message, creating a nested structure where signatures are embedded within the message layers.
2Productivity
If the communication device signs the message before server modification, then the signing process is simple and fast, but the authentication is incomplete since the signed message differs from the sent message
Solution Approach 1:
The communication device performs preliminary signing of the first portion before the server modifies the message. This preliminary digital signature is then preserved and included in the final message, allowing verification of the original content while accommodating subsequent server additions.
Solution Approach 2:
The server provides feedback by generating a second digital signature that covers the complete message including both the original portion and added content. This creates a verification chain where recipients can validate both the original message integrity and the server's modifications.
Data Source
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AI summary
A system and method of signing a message to be sent from a first communication device to a destination via a second communication device. The message includes a first portion on the first communication device and a second portion on the second communication device. The method includes receiving at the second communication device the first portion of the message and a first signature for the first portion from the first communication device; combining the first portion and the second portion to form the message; obtaining a second signature for the message; and sending the first signature, the second signature and the message from the second communication device to the destination.