Cyber Defense eMagazine May 2019

human body. Its true advantages are low attenuation and full confinement of signals inside the human
body, offering more security and interference-free communication.
Most importantly, we found that our prototype drastically reduced over-the-air leakage and adversarial
detection of signals, making the transmission of biometric data impervious to sniffing attacks while still
maintaining transmit power levels deemed safe for human operation. Ultimately, GC-signals are confined
within the body and cannot be intercepted unless the user is in direct contact with the medium.
A key attribute of the system is its capability to secure data transmission for biological signals that have
potential use for biometric authentication systems. Specifically, our prototype consists of a microcontroller
unit (MCU) with supporting analog front-end hardware for signal modulation and detection. The transmitter
MCU is configured to transmit with a biometric signature unique to the individual (in our scenario, the
electrocardiogram signal). Other signatures might include, but are not limited to, electromyogram signals
(EMAG), bio-impedance and galvanic skin response (electrodermal activity).
The adoption of biophysical signals, to either supplement or act as a stand-alone solution, as opposed to
current antiquated authentication systems, lies at the cutting edge of biometric research for medical and
commercial applications.
In the commercial space, there are wearable authenticators designed to work with other devices (desktop
computers, doors, et al.) and perform authentication based on proximity to the locked device. Think of a
fitness device or other wearable band that employs a biological signal as a biometric. Once a user is
authenticated, the system will use wireless channels, such as Bluetooth Low Energy and NFC, to pair
with devices running the supported application.
Wearables are also being developed that use a person’s behavior for authentication. Whether it’s
something like a fingerprint scanner, a heartbeat sensor or an accelerometer measuring your gait,
biometrics attempts to measure aspects of what you are, and those can be used for authentication.
Devices in the fitness category can do this sort of measurement and are already gaining popularity.
Combining biometrics with existing authentication factors can result in a very secure system that is nearly
impossible to fool.
Recently, the use of alternative IBC solutions has been employed to perform similar operations. However,
as we have demonstrated within our work, those signals are still susceptible to outside and environmental
influence.
We describe our new biometric authentication system in a paper titled “Secure On-skin Biometric Signal
Transmission using Galvanic Coupling.” Our team, which includes engineers from Draper, Federal
University of Parana and Northeastern University, presented our system at IEEE INFOCOM 2019 in
Paris, France.
Funding for development of this technology was provided by a U.S. National Science Foundation under
Grant No. CNS-1740907.
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