Researchers Foil Fingerprint Thievery With Made-For-TV Science

Even more fingerprint news today! How many times have you seen a crime drama where the bad guy lures a victim just to get ahold of their fingerprint, either by cutting off their digit or making an imprint? The fingerprint is then used to steal the victims identity and unlock secrets guarded by the ever important fingerprint scanner. While many of the things you seen the movies and on television seem far-fetched, this scenario is actually something that has played out in real life.

But now, researchers in Germany have come up with a way to foil criminals intent on manipulating fingerprint scanners. Researchers at Dermalog Identification Systems have discovered that there is a difference in the amount of light that gets absorbed by living tissue versus tissue that is dead (like that of a severed finger). The process is based on the fact that living tissue will blanch when blood is squeezed out of capillaries, but dead tissue won’t.

In a study published in Forensic Science International, the researchers explain that a living finger absorbs LED light at 550 nanometers when it is first placed on a fingerprint scanner. When the living finger is pressed down, making full contact with the sensor, the skin blanches and absorbs 1450 nanometers of light. The researchers compared this to three cadaver fingers, none of which changed in the amount of light absorbed when pressed firmly against the scanner.

But in addition to telling the difference between living tissue and dead tissue, another team of researchers are also working on a new way to foil criminals using finger imprints in gels or rubber. Led by Marcela Espinoza at the Institute of Police Science in Switzerland, researchers are developing an algorithm that can distinguish between a fingerprint mold and an actual finger based on the noticeable spaces between the ridges and furrows of the print that occur when the print is copied.

The work by both research teams comes as a time when the International Standards Organization is drafting guidelines for secure biometrics. Even if these new fingerprint verification methods don’t make it into the new guidelines, we’re sure we’ll see them on an episode of CSI sometime soon.

(via New Scientist, photo via PopSci)