Biometrics: Perspiring Fingers

(new biometrics program will look for perspiration on fingers)

Perspiring fingers and/or hands could someday prevent criminals from getting into bank accounts or illegally entering restricted areas

Researchers at Clarkson University have found that fingerprint readers can be deceived by images of fingers lifted with "Play-doh" or gelatin or a model of a finger molded out of dental plaster. The group even assembled a collection of fingers cut from the hands of cadavers.

In a systematic test of more than 60 of the carefully crafted samples, the researchers found that 90 percent of the fakes could be passed off as the real thing, but when researchers enhanced the reader with an algorithm that looked for evidence of perspiration, the false-verification rate dropped to ten percent.

The idea of using perspiration is promising as a way to interfere with the methods used by criminals because such sweating follows a pattern that can be modeled. In live fingers, perspiration starts around the pore and spreads along the ridges, creating a distinct signature of the process.

The algorithm, created by Stephanie Schuckers, associate professor of electrical and computer engineering at Clarkson, detects and accounts for the pattern of perspiration when reading a fingerprint image.

Fingers of the dead, of course, don't perspire

"Living" digit detection is based on the recognition of physiological functions as signs of life and so it was thought by researchers that specific changing moisture patterns resulting from perspiration would occur, but a cadaver or spoof fingerprint image would not.

The research, funded by a $3.1 million grant from the National Security Agency and conducted in collaboration with other universities, is part of an ongoing effort to improve biometric authentication and identification.

Fingerprint readers essentially take a picture of a fingerprint and match it to a sample in the database. To get around spoofs involving lifted fingerprints, NEC researchers have developed technology that actually takes a picture of the tissue underneath the fingertip to get a three-dimensional image that can be matched against a database sample. Fujitsu has developed an authentication technology that looks at vein patterns.

Although biometric identification technologies continue to improve, each has its own flaws. Voice authentication is fairly accurate and tough to spoof, say advocates, but it can be affected by a bad phone connection. Iris scans work well, but are commercially impracticable.

Face scanning is actually less accurate than most, but consultants for the U.S. State Department say that the technology was chosen for electronic passports because that particular identity test seems to make people feel less like criminals.

—Based on an article written by Michael Kanellos in News.Com; December 21, 2005.

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