Bluetooth Proximity Authentication via Time-Deferred Scrambling

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Solution Overview

Problem

Existing tracking device and tag systems lack sufficient authentication, making them susceptible to identity spoofing and unauthorized access, as they do not provide adequate verification of the authenticity of associated tags.

Innovation Solution

Implementing a time-deferred scrambling method where tracking devices send proximity detection requests and measure the round trip time of responses from tracked devices, using a shared key to generate and verify delays, ensuring only authentic devices can match the expected delay patterns, thereby enhancing security through accurate identification and proximity detection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional wireless communication protocols are used for tracking devices and tags, then ease of operation and device compatibility are improved, but security and authentication reliability deteriorate due to susceptibility to identity spoofing

Engineering Contradiction:

Improveauthentication reliabilityVSAvoidauthentication mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by establishing shared secrets between tracking devices and tags before actual tracking operations. These shared secrets are used to generate time-deferred scrambling codes that will be used for authentication, preparing the security mechanism in advance to prevent spoofing attacks.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The authentication mechanism uses dynamic time-deferred scrambling codes that change over time based on the shared secret and current time. This dynamic approach ensures that authentication credentials are not static and cannot be easily replicated by spoofing devices, as the authentication code evolves continuously.

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If simple pairing protocols are used between beacons and tags, then ease of operation is improved, but security against spoofing deteriorates due to lack of adequate authentication

Engineering Contradiction:

Improvepairing operation simplicityVSAvoididentity verification reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system introduces an intermediary authentication mechanism using time-deferred scrambling codes derived from shared secrets. This intermediary layer verifies the authenticity of tags without requiring complex user interaction, automatically mediating between the simplicity of pairing and the need for reliable identity verification.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes the parameter of authentication from static device identifiers to dynamic time-based scrambling codes. This parameter change allows the system to maintain simple operation while significantly improving identity verification reliability, as the authentication credential becomes time-dependent and cannot be spoofed.

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If no authentication mechanism is implemented, then device complexity is reduced, but susceptibility to unauthorized access and spoofing increases

Engineering Contradiction:

Improveauthentication system complexityVSAvoidspoofing vulnerability

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces physical security mechanisms with cryptographic authentication using time-deferred scrambling codes. This substitution provides robust protection against spoofing without requiring complex physical security infrastructure, using mathematical principles instead of mechanical security measures.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method significantly reduces the ability of unauthorized devices to spoof identities, ensuring secure communication and operations between tracking and tracked devices by accurately verifying the authenticity of tagged devices.

Implementation Method 1

measure the round trip time of responses from tracked devices

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS10341865B2Distance estimation and authentication for Bluetooth systems, and devices

Publication Date: 2019.07.02 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

Distance estimation and authentication are provided for Bluetooth systems and devices. Proximity detection requests are transmitted using a transceiver of a tracking device. Reply messages are received from a tracked device. Designated delay values are generated, and round trip times associated with the reply messages are determined based, at least in part, on the designated delay values and time stamps associated with the reply messages. An authenticity metric associated with the tracked device is generated based, at least in part, on the round trip times.