AirSign: Smartphone Authentication by Signing in the Air

Area of Science:

• Human-computer interaction
• Biometric authentication
• Mobile security

Background:

• Current smartphone authentication methods often lack convenience, intuitiveness, or robust security.
• There is a need for novel authentication technologies that integrate seamlessly into daily user interactions.
• Existing biometric solutions may require specialized hardware or intrusive user actions.

Purpose of the Study:

• To introduce AirSign, a new user authentication technology for smartphones.
• To enable convenient, intuitive, and secure user authentication through in-air signatures.
• To leverage existing smartphone sensors (acoustic and motion) without additional hardware.

Main Methods:

• AirSign utilizes the earpiece speaker to transmit inaudible acoustic signals.
• Built-in microphones receive echoes to map signature and hand geometry.
• Acoustic echo features and motion sensor data are combined for authentication.
• User authentication is performed based on unique features extracted from sensor data.

Main Results:

• The study collected registered, genuine, and forged signatures from 30 participants.
• AirSign achieved a 97.1% F-score in distinguishing genuine from forged signatures.
• The system requires only seven signatures during the registration phase for effective authentication.

Conclusions:

• AirSign provides a promising solution for secure and user-friendly smartphone authentication.
• The technology effectively utilizes acoustic and motion sensing for biometric identification.
• The low registration requirement and high accuracy demonstrate practical viability for widespread adoption.