By in Technology Review
Paper-thin
fingerprint scanners could soon make cell phones, USB memory, and
credit cards more secure. The new scanners, developed by Nanoident
Technologies, a startup based in Linz, Austria, detect patterns and
blood content in the tissue within the finger. This makes them much
harder to fool than ordinary fingerprint readers, which measure only
the ridges and contours of fingerprints.
Nanoident's
technology, which could be available in consumer devices within two
years, takes advantage of inkjet technology to print light sensors,
light emitters (similar to the organic light-emitting devices used in
some cell phone displays), and electronic circuitry for memory and
signal processing. This combination makes it possible to illuminate an
object and measure the reflected light, says CEO Klaus Schroeter. The
printing-based manufacturing process is far cheaper than the
process used with silicon-based electronics -- the sensors will cost
less than two dollars in cell phones, and in large-volume "smart card"
applications, less than a dollar, Schroeter says. Furthermore, the
devices can be printed on a wide variety of surfaces, such as glass,
plastic, and paper. The
scanners combine information from the surface of the finger -- the
fingerprint -- and the underlying tissue and blood. This deeper
information is obtained by illuminating the finger with different
wavelengths of light, some reflecting off the surface, and others,
toward the red end of the color spectrum, penetrating deeper, allowing
the scanner to extract data from beneath the skin. Combining
information about the tissue structure, which Schroeter says is unique
to each person, with conventional fingerprint data improves the
accuracy of the scanner. The company’s sensors are more than 99 percent
accurate, Schroeter says, while conventional fingerprint detectors are
inaccurate for around three percent of the population. The
more detailed measurements make the sensors difficult to fool.
According to Peter Honeyman, scientific director of the Center for
Information Technology and Integration at the University of Michigan,
making artificial fingers to trick conventional sensors is easy -- and
an increasing threat to fingerprint-based security. But since such a
fake finger does not have the tissue and blood of a real finger,
Nanoident’s sensor could tell the difference. By using more
than one measurement -- or "multi-modal biometrics" -- Honeyman says
technologies such as Nanoident's could produce more secure fingerprint
systems. But he also cautions that security measures can eventually be
cracked -- especially if the payoff is large enough to justify the
effort and investment. Schroeter
says his company is developing the technology in cooperation with a
major producer of cell-phone parts. And they plan to build scanners
into "smart" credit cards or cash cards. In this application, the
printed electronics would compare the scan to data about the finger
stored onboard the card. Banks considering the use of smart cards
prefer storing information on a card to in a centralized database to be
accessed via a card reader, since such a database could be vulnerable,
Schroeter says. The
company plans to use its printed light sensors and emitters and
electronics for other applications, too, including biochips. Currently,
these chips, which are widely used in biomedical research, have arrays
of material that fluoresce when target molecules are present, and
require expensive readers. Cheaper printed scanners could be useful for
relatively simple applications, such as allergy tests.
