Secure Location Indicators for Privacy-Preserving Proximity Detection

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Solution Overview

Problem

Existing location-based services face challenges in notifying users of nearby portable devices without compromising user privacy, as current methods may reveal geographic locations even when secure indicators are intercepted.

Innovation Solution

A method where portable devices generate secure location indicators by applying cryptographic functions to quantized geographic coordinates and pseudo-random noise derived from environmental entropy, allowing servers to identify proximate devices without determining the exact location, thus maintaining user privacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If portable devices report their geographic location to a network server, then the server can identify nearby users and provide location-based services, but the user's privacy is compromised as the server and potentially third parties can determine the exact geographic location

Engineering Contradiction:
Improveability to identify nearby usersVSAvoidprivacy compromise
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces secure location indicators as an intermediary representation of geographic location. Instead of devices reporting actual coordinates, they generate cryptographic indicators that serve as a mediator between the need for location-based matching and privacy protection. The server processes these indicators to identify nearby devices without ever obtaining the actual geographic coordinates, thus resolving the contradiction between service functionality and privacy preservation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a cryptographic copy or representation of location data through secure location indicators. These indicators are derived from quantized coordinates and environmental entropy, forming a surrogate that preserves the proximity-matching functionality while eliminating the harmful exposure of actual location information. The server operates on these copies rather than the original sensitive data.

Inventive Principle:
Principle #26Copying

2Object-affected harmful factors

If portable devices quantize geographic coordinates to reduce precision, then privacy is improved by hiding exact location, but the ability to accurately identify nearby devices deteriorates

Engineering Contradiction:
Improveprivacy protectionVSAvoidlocation accuracy for proximity detection
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent transforms the location representation parameters by quantizing continuous geographic coordinates into discrete cells and combining them with environmental entropy. This parameter transformation creates secure location indicators that maintain sufficient discrimination capability for proximity detection while inherently limiting the precision of location information. The quantization process changes the parameter scale from continuous high-precision coordinates to discrete lower-precision cells.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent combines multiple elements (quantized location coordinates and environmental entropy) to create a composite secure location indicator. This composite structure integrates the spatial information needed for proximity detection with random entropy data, producing a unified indicator that simultaneously provides privacy protection and maintains accurate nearby device identification capability.

Inventive Principle:
Principle #40Composite materials

3Object-affected harmful factors

If portable devices use cryptographic functions to generate secure location indicators, then privacy is preserved, but the device complexity increases due to additional processing requirements

Engineering Contradiction:
Improveprivacy preservationVSAvoidcryptographic processing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent segments the secure location indicator generation process into distinct components: quantization of coordinates, collection of environmental entropy, and cryptographic combination. This segmentation allows each component to be handled separately and efficiently, reducing the overall computational burden compared to a monolithic cryptographic approach. The environment sensor data is collected separately and then combined with quantized location data through cryptographic functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enables devices to generate their own secure location indicators using locally available resources (environmental sensors and device clock) combined with quantized coordinates. Each device independently produces its own indicator without requiring complex centralized key management or external cryptographic services, allowing the system to scale efficiently while maintaining strong privacy protections through distributed self-service cryptography.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2772080B1Finding nearby users without revealing own location
Publication Date: 2016.08.10 GOOGLE LLC
  • EP2772080B1 patent drawingFigure 1
  • EP2772080B1 patent drawingFigure 2
  • EP2772080B1 patent drawingFigure 3~4

AI summary

A method can be implemented in a portable device operating in a wireless communication network. The method is for securely reporting an indication of a current geographic location of the portable device to a server without revealing the current geographic location of the portable device to the server, where the server is communicatively coupled to the communication network. The method includes generating a pseudo-random value using a signal from an environment in which the portable device operates, generating a location descriptor based on the current geographic location of the portable device, applying a cryptographic function to a combination of the pseudo-random value and the location descriptor to generate a secure location indicator for the portable device, and causing the secure location indicator to be electronically transmitted to the server via the communication network.