Biometric systems have reached a point where they can offer very accurate verification when a
legitimate sample is presented. However, these systems can be easily deceived by imitations of an authorized sample.
Fake fingerprints (gummy fingers) can fool most commercial systems. Images of synthetically generated fingerprints
are almost indistinguishable from real ones and are actually used to evaluate fingerprint verification algorithms.
Certain capacitive based fingerprint sensors have been tricked simply by breathing on the sensor to reactivate a latent,
authorized image. Another spoofing method uses a replica of an authorized user’s finger. These false fingers are easy
to make and can be produced with or without the assistance of an authorized user. A method of establishing the liveness
of the biometric data would address many of the existing shortcomings.
This study proposes using pulse, measured via pulse oximetry, as a means of determining if a sample
presented for authentication is part of a living person. The setup for this study used two sensors,
one for recording the fingerprint and the other for monitoring pulse. Fake fingers made out of
silicone rubber and gelatin, two methods shown to be effective against current systems, were tested against
the experimental setup with and without the liveness detection component activated.
Preliminary studies have shown that this type of system is more resistant to attacks.
If no live finger was placed behind the fake fingerprint the system rejected the sample 100% of the time.
While the commercial sensors were used to test the validity, our research goal is to integrate this capability
within the sensor itself.
