Finger vibrations used to make any hard surface a biometric security device

A technique that uses finger vibrations instead of fingerprints for biometric security can turn any hard surface into a smart access system to verify users, say its developers.

The development team at Rutgers University in New Jersey believes the low-cost security system, dubbed VibWrite, could eventually be used to gain access to homes, apartment buildings, cars or appliances: basically anything with a solid surface.

“Everyone’s finger-bone structure is unique, and their fingers apply different pressures on surfaces, so sensors that detect subtle physiological and behavioural differences can identify and authenticate a person,” said Professor Yingying Chen.

The market for smart security access systems is expected to grow rapidly, reaching nearly $10bn (£7.6bn) by 2022. Today’s smart security access systems mainly rely on devices such as intercoms, cameras, cards or fingerprint readers to authenticate users. But these systems require costly equipment, complex hardware installation and diverse maintenance needs.

The goal of VibWrite is to allow user verification when fingers touch any solid surface, and builds on a touch-sensing technique by using vibration signals.

It’s different from traditional, password-based approaches, which validate passwords instead of legitimate users, as well as behavioural biometrics-based solutions, which typically involve touch screens, fingerprint readers or other costly hardware and lead to privacy concerns and “smudge attacks” that trace oily residues on surfaces from fingers.

“Smart access systems that use fingerprinting and iris-recognition are very secure, but they’re probably more than 10 times as expensive as our VibWrite system, especially when you want to widely deploy them,” said Chen, who works in the School of Engineering and is a member of the Wireless Information Network Laboratory (WINLAB) at Rutgers University-New Brunswick.


VibWrite allows users to choose from PINs, lock patterns or gestures to gain secure access, the paper says. The authentication process can be performed on any solid surface beyond touch screens and on any screen size.

It is resilient to “side-channel attacks” - when someone places a hidden vibration receiver on the surface or uses a nearby microphone to capture vibration signals. It also resists several other types of attack, including when an attacker learns passcodes after observing a user multiple times.

VibWrite is positioned as a low-cost, minimal-power system as all it needs to operate is an inexpensive vibration motor and receiver.

Both hardware installation and maintenance are easy according to the developers, and “VibWrite probably could be commercialised in a couple of years,” Chen said.

During two trials, VibWrite verified legitimate users with more than 95 per cent accuracy and the false positive rate was less than 3 per cent, although this is currently significantly higher than conventional fingerprint scanners.

The current VibWrite system also needs improvements because users may need a few attempts to pass the system. To improve performance, the Rutgers-led team will deploy multiple sensor pairs, refine the hardware and upgrade authentication algorithms. They also need to further test the system outdoors to account for varying temperatures, humidity, winds, wetness, dust, dirt and other conditions.

Earlier this year a team demonstrated a 3D fingerprint scanner that boasts faster speed and accuracy than traditional devices and is designed for use by law enforcement. 

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