Twice-Signed Data Usage Tokens for Secure App Data Access

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Solution Overview

Problem

Existing systems lack robust mechanisms to ensure secure and transparent data access control for applications with varying trust levels, particularly in devices with multiple applications, leading to potential unauthorized access and misuse of sensitive data.

Innovation Solution

Implementing a twice-signed data usage token that includes signatures from both the application's publisher and the device's data-access authorization system to validate and authenticate data access requests, ensuring that only authorized uses of data are permitted.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional data access control mechanisms are used, then device complexity is reduced, but data security and reliability are compromised

Engineering Contradiction:
Improvedata securityVSAvoidaccess control mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements nested digital signatures where an authorization system signature envelops and validates the publisher signature. The twice-signed token structure creates nested layers of authentication - the publisher signs the data usage terms first, then the authorization system signs the publisher's signature, creating a nested verification hierarchy that enhances security without requiring complete redesign of the access control architecture

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent introduces a data-access authorization system as an intermediary between the application publisher and the device. This intermediary validates publisher signatures and issues authorized access tokens, mediating the trust relationship and preventing direct unauthorized access while maintaining a manageable complexity through specialized intermediate verification

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If applications have broad data access permissions, then ease of operation is improved, but harmful factors increase due to potential unauthorized access

Engineering Contradiction:
Improvedata access便利性VSAvoidunauthorized data access
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent implements preliminary authorization where publishers must pre-sign data usage terms and the authorization system pre-validates these terms before actual data access occurs. The twice-signed token is created in advance with defined usage parameters, ensuring that data access is granted only after preliminary verification of the application's intended use, preventing unauthorized access while maintaining operational ease for legitimate applications

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a feedback mechanism where the authorization system validates publisher signatures and provides authorization decisions back to the device. The twice-signed token contains verified usage terms that feed back into the access control decision, ensuring that data access is granted only when the feedback verification confirms legitimate use, thereby reducing harmful factors while maintaining ease of operation for authorized applications

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4121882B1Restricting data access
Publication Date: 2025.11.12 GOOGLE LLC
  • EP4121882B1 patent drawingFigure 1
  • EP4121882B1 patent drawingFigure 2
  • EP4121882B1 patent drawingFigure 3

AI summary

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for validating an application's data access request. One of the methods includes receiving, for an application, a request for access to data collected by a device; determining an identifier for the application and a declared use of the data by the application based on contents of a twice-signed data usage token for the application; and controlling the application's access to the data, including: enabling access to the data when (i) both signatures of the twice-signed data usage token have been validated and (ii) the declared use of the data matches an authorized use of the data; and preventing the application from accessing the data when (i) either signature of the twice-signed data usage token has not been validated or (ii) the declared use of the data fails to match the authorized use of the data.