Acoustic Proximity Authentication via Time-of-Flight
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Solution Overview
Problem
Existing proximity-based authentication methods are unreliable due to inaccuracies in distance measurement and vulnerability to attacks, such as spoofing and man-in-the-middle attacks, especially in applications requiring high security.
Innovation Solution
A method using modulated and encrypted audible signals to establish a secure connection between devices, allowing for accurate and continuous distance measurement between a trusted device and an authenticating device, employing timestamps and time differences to estimate distance and securely lock or unlock the authenticating device based on user-configured distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If RSS-based proximity detection is used, then device complexity is reduced, but measurement precision and reliability deteriorate
Solution Approach 1:
The patent replaces RSS-based electromagnetic signal strength measurement with acoustic wave-based time-of-flight measurement. The transmitting device sends acoustic signals that are reflected by the target device, and the distance is calculated based on the time delay of the reflected signals, providing more accurate and reliable proximity detection.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium for distance measurement. Instead of directly measuring electromagnetic signal strength, the system uses acoustic signals as carriers to transmit timing information, enabling precise distance calculation through time-of-flight measurement while maintaining system feasibility.
2Ease of operation
If basic proximity detection is used, then ease of operation is improved, but security and reliability worsen due to spoofing attacks
Solution Approach 1:
The patent implements preliminary device pairing and acoustic fingerprint registration before actual authentication. During the pairing phase, devices exchange and store each other's acoustic characteristics. This preliminary action enables the system to verify device identity through acoustic fingerprint matching during authentication, preventing spoofing attacks while maintaining ease of use.
Solution Approach 2:
The patent employs feedback mechanisms where devices continuously exchange acoustic signals and verify received signals against stored fingerprints. The system provides feedback on authentication status and adjusts security responses based on verification results, enabling automatic acceptance of legitimate devices and rejection of spoofing attempts.
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
Provides a secure and accurate means to determine device proximity, preventing unauthorized access by ensuring devices lock when beyond a safe distance, thus enhancing security and reliability in authentication processes.
Implementation Method 1
a transmitting device emits a first acoustic signal at a first time and receives a first acoustic signal reflected from a receiving device
Implementation Method 2
receives a first acoustic signal reflected from a receiving device
Data Source
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AI summary
An accurate distance between two devices can be determined in continuous and secure manner using modulated audible signals containing time-based information. This calculated distance can be used to lock and unlock one of the two devices such that if one of the devices, such as a smart phone or smart watch, is beyond a pre-configured distance from the other device, such as a laptop or tablet, the other device locks and may display a message to the user. The modulated messages contain time difference data of audible signal emission and receiving times which are used by each device to calculate an accurate estimate of the distance between the two devices.