I lead a team of developers where I work. We have lately been working on voice biometric access restrictions to computer systems. In our initial research we looked at fingerprint based systems.
The biggest liability to them is how easily they can be defeated. You finger leaves enough oil behind to provide a copy of your print. Place a balloon with some 95° water on it, and it will frequently open.
Forensic analysis works off the skin oil as well. Your fingerprints can be lifted from a number of places, reproduced on a variety of mediums, and then used to imitate your presence. It's one of the easiest biometric areas to fake. If someone wears your prints over their fingers, they will be nearly indistinguishable from real fingerprints.WOW!!! That's interesting.
So, if I'm understanding this correctly, the oil left behind from your last finger scan leaves an impression of your fingerprint. But, the scanner is also looking for warmth, so the 95 degree balloon provides the warmth for the scanner which will then grant access.
hhhmmm...