Scientists Develop Stretchable, Body-powered Biometric Authentication Technology

A team of researchers has unveiled a new approach to biometric authentication that leverages a stretchable triboelectric nanogenerator (STENG). Designed with micro-nano hierarchical interfaces, the device can harvest energy from human movement while also serving as a self-powered sensor for biometric applications.

The study, led by researchers from China, Japan, and Tsinghua University, offers an innovative twist to biometric technology, introducing a potential tool for specialized wearable applications.

The STENG combines two advanced materials: a micro-pyramidal polydimethylsiloxane (PDMS) layer and a thermoplastic polyurethane (TPU) nanofiber film. These components form a stretchable, flexible, and highly sensitive interface that generates electricity through mechanical input, such as tapping or bending. While the energy output isn’t sufficient to power high-demand devices, the researchers demonstrated its ability to power small electronics like sensors. More intriguingly, the STENG doubles as a sensor, enabling it to measure unique biometric traits such as typing patterns.

In their study, the team created a prototype wearable keyboard comprising nine STENG “keys.” This keyboard captured users’ keystroke dynamics, such as force, timing, and frequency, to distinguish between individuals. By employing a machine learning algorithm, specifically a Support Vector Machine (SVM), the system achieved a user identification accuracy of 93.21 percent. Even more impressive, it detected “intruders” — users who were not part of the training dataset — with 81.50 percent accuracy. While not flawless, these results highlight the potential for STENG-based devices to add an extra layer of security to digital identity systems.

Unlike traditional biometric systems, which rely on external power sources or static sensors, the STENG operates independently by harvesting energy from mechanical activity. The researchers suggest that such self-powered devices could prove useful in specific scenarios, such as remote areas or environments requiring lightweight, flexible technology. However, the study acknowledges some challenges, including variability in keystroke consistency, which can slightly impact accuracy.

Although the immediate applications of the STENG are limited, the underlying technology demonstrates interesting possibilities for biometrics. For instance, STENG-based systems could complement existing solutions by providing an additional mode of authentication or enabling security features in wearable devices. The team also sees potential for monitoring physical activity and detecting physiological patterns, expanding its utility beyond identification.

This research aligns with broader trends in biometric innovation, where energy-efficient, flexible, and adaptable technologies are becoming increasingly important. As wearable devices and Internet of Things (IoT) applications continue to grow, such solutions could carve out niche applications in specialized industries, such as healthcare or personal security.

Source: Nature

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November 26, 2024 – by Cass Kennedy