Acoustic and Surface Vibration Authentication via Transfer Function Analysis
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Solution Overview
Problem
Current authentication systems for portable devices are either cumbersome or non-robust, as they can be accessed by unauthorized individuals who overhear or record voice PINs or passphrases, and the 'trusted device' option is vulnerable to theft and unauthorized access.
Innovation Solution
A system that uses both acoustic and surface wave microphones to authenticate users by analyzing the unique transfer function between the two signals, which is fixed based on the user's head and neck geometry, density, and tissue composition, providing a more secure and hands-free authentication method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If audible PIN codes or passphrases are used for authentication, then ease of operation is improved, but security is worsened since nearby persons may overhear or record the utterance
Solution Approach 1:
The authentication system segments the authentication signal into two separate transmission paths: acoustic waves through air and surface waves through bone/tissue. By dividing the single authentication channel into multiple independent paths, the system captures the utterance through different physical media, making it difficult for attackers to compromise both paths simultaneously.
Solution Approach 2:
The system transitions from single-dimensional acoustic authentication to two-dimensional authentication by adding surface wave detection through bone conduction. This dimensional expansion creates a more robust authentication space where the surface wave component provides an additional layer that cannot be easily replicated by traditional acoustic recording attacks.
2Reliability
If fingerprint readers or iris readers are used for authentication, then security is improved, but ease of operation is worsened since they cannot be used hands-free or unobtrusively
Solution Approach 1:
The system enables self-service authentication by utilizing the user's own body (head and neck tissues) as part of the authentication mechanism. The surface wave microphone leverages the natural bone conduction path from the user's vocal tract to the microphone, requiring no manual interaction while capturing biometric characteristics inherent to the user's anatomy.
Solution Approach 2:
The surface wave microphone serves multiple functions: it detects surface waves for authentication, utilizes the user's head and neck as a transmission medium, and captures voice characteristics without requiring manual device handling. This multi-functionality allows the same component to provide both biometric authentication and hands-free operation.
3Ease of operation
If the 'trusted device' option is used to make authentication unnecessary, then ease of operation is improved, but security is worsened because the device can be surreptitiously accessed when the trusted entity is within Bluetooth range but not within the user's sight
Solution Approach 1:
The system applies local quality by using the unique physical characteristics of the user's head and neck anatomy as a localized biometric identifier. The surface wave transmission path is specific to each user's bodily structure, creating a localized authentication factor that cannot be remotely replicated or exploited, unlike Bluetooth trust relationships that depend on proximity alone.
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 approach enhances security by making it difficult for unauthorized users to replicate the authentication process, as the transfer function is unique to each individual and requires precise biometric data, reducing the likelihood of theft and unauthorized access.
Implementation Method 1
A surface vibration microphone is provided in the portable communication device. The surface vibration microphone is configured to contact a surface of the user and detect a surface wave generated by the user's head and neck tissues in response to an uttered sound.
Implementation Method 2
The acoustic microphone is configured to collect an acoustic wave from the uttered sound
Implementation Method 3
The processor is configured to analyze a transfer function between the acoustic wave and the surface wave
Data Source
AI summary
Systems and methods for authorizing a user of a portable communications device entail sampling a user utterance via both an air mic (audio mic) and a conduction mic (surface mic or bone conduction mic). The difference between these signals is unique to each user since the tissues of each user will differ with respect to audio conduction. This difference may be characterized via a transform including magnitude, phase and time delay components. If the transform for a prospective user matches a stored transform for an authorized user, then the prospective user may be granted access.