Returning Device Recognition With Hash-Based Attribute Matching

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Solution Overview

Problem

Existing device recognition systems fail to accurately identify returning devices due to changes in device characteristics, are vulnerable to anonymization and spoofing attacks, leading to high False Accept Rate (FAR) and False Reject Rate (FRR), causing inconvenience and unauthorized access.

Innovation Solution

A system that maintains a database of unique device attribute groups, uses pseudorandom device identifiers, and employs secure communication paths to verify device integrity, minimizing changes in device attributes before re-identification, and detects spoofing attacks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If device characteristics are collected and transmitted to the server for recognition, then device identification capability is improved, but the system becomes vulnerable to anonymization and spoofing attacks

Engineering Contradiction:
Improvedevice identification accuracyVSAvoidanonymization and spoofing attacks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by pre-computing and storing multiple possible hash values for each device attribute group in the database before actual device recognition occurs. When a device attribute group is first observed, the system pre-generates hash values for all possible transformations and stores them in advance, enabling rapid and accurate matching even when attributes change, while preventing spoofing attacks through cryptographic hashing.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If device characteristics are stored and compared for recognition, then returning devices can be identified, but False Accept Rate and False Reject Rate increase when attributes change

Engineering Contradiction:
Improvedevice recognition reliabilityVSAvoiddevice identification accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by transforming device attributes into hash values that remain consistent despite changes in the original attributes. The system observes that device attributes may change over time (e.g., software updates, carrier changes), so it uses cryptographic hashing to create stable identifiers that preserve the ability to recognize returning devices while being insensitive to non-critical attribute variations, thereby reducing both FAR and FRR.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If multiple device attributes are monitored for recognition, then recognition coverage is improved, but system complexity and computational overhead increase

Engineering Contradiction:
Improverecognition coverageVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical system of storing and comparing multiple raw device attributes with a cryptographic hash-based identification system. Instead of maintaining and querying large databases of multiple attribute values, the system computes hash values from device attributes and stores these compact representations, significantly reducing storage requirements and computational complexity while maintaining or improving recognition coverage.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3420694B1Systems and methods for recognizing and categorizing a device
Publication Date: 2025.09.10 ACCERTIFY INC
  • EP3420694B1 patent drawingFigure 1~2A
  • EP3420694B1 patent drawingFigure 2B~3
  • EP3420694B1 patent drawingFigure 4

AI summary

A system for detecting whether a device seeking communication with a server is a returning device that previously communicated with the server includes a database that stores groups of device attributes based on observable device characteristics and unique identifiers. The database is generally not accessible to the devices. Each attribute group and the associated device identifier (DID) can uniquely identify a particular device, and the associated DID is generally not derivable from the attributes. The database may satisfy a uniqueness property so that each attribute value in the database may also uniquely identify a device.