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05-19-2005, 07:42 AM
How to fake fingerprints?
In order to fake a fingerprint, one needs an original first. Latent fingerprints are nothing but fat and sweat on touched items. Thus to retrieve someone elses fingerprint (in this case the fingerprint you want to forge) one should rely on well tested forensic research methods. Which is what's to be explained here. (Figure 1).
http://www.ccc.de/biometrie/images/tiny_01-fingerabdruck+mate.jpg
Figure 1: Fat residue from fingerprint (http://www.ccc.de/biometrie/images/small_01-fingerabdruck+mate.jpg?language=en)
A good source of originals for our counterfeits are glasses, doorknobs and glossy paper. The standard method of forensic research makes them visible: Sprinkling it with colored powder, which sticks to the fat (Figure 2).
http://www.ccc.de/biometrie/images/tiny_02-fingerabdruck+grafit.jpg
Figure 2: Visualisation with graphite powder (http://www.ccc.de/biometrie/images/small_02-fingerabdruck+grafit.jpg?language=en)
Another solution involves Cyanoacrylat, the main ingredient of superglue. A small amount thereof is poured into a bottlecap, which is then turned upside down and put over the fingerprint. (Figure 3).
http://www.ccc.de/biometrie/images/tiny_03-mate+deckel.png
Figure 3: Visualisation with superglue (http://www.ccc.de/biometrie/images/small_03-mate+deckel.png?language=en)
The Cyanoacrylat gasses out and reacts with the fat residue to a solid, white substance (Figure 4).
http://www.ccc.de/biometrie/images/tiny_04-finger+zyanoacrylat.png
Figure 4: Print after Cyanacrylate processing (http://www.ccc.de/biometrie/images/small_04-finger+zyanoacrylat.png?language=en)
The further treatment involves scanning/photographing (Figure 5) and a bit of graphical refurbishment (Figure 6).
http://www.ccc.de/biometrie/images/tiny_05-finger+cyanoacrylate+kamera.png
Figure 5: Digitalising the print (http://www.ccc.de/biometrie/images/small_05-finger+cyanoacrylate+kamera.png?language=en)
http://www.ccc.de/biometrie/images/tiny_06-finger+nachbearbeiten.png
Figure 6: Brushing up the image of the print (http://www.ccc.de/biometrie/images/small_06-finger+nachbearbeiten.png?language=en)
The goal is to get an exact image of the fingerprint, for further use as mold, out of which the dummy is made. The easiest way is to print the image on a transparency slide (the ones normally used for an overhead projector) with a laser printer. The toner forms a relief, which is later used similar to letter press printing. Wood glue is suitable for producing the dummy (Figure 7)
http://www.ccc.de/biometrie/images/tiny_07-finger+holzleim.png
Figure 7: Wood glue for the dummy (http://www.ccc.de/biometrie/images/small_07-finger+holzleim.png?language=en)
A small dash of glycerene may be used to optimize humidity and workability. After thorough mixing, the dummy gets coated with a thin layer of the compound (Figure 8,9).
http://www.ccc.de/biometrie/images/tiny_08-attrappe03.jpg
Figure 8: Covering the dummy with wood glue (http://www.ccc.de/biometrie/images/small_08-attrappe03.jpg?language=en)
http://www.ccc.de/biometrie/images/tiny_09-attrappe04.jpg
Figure 9: Glue layer on the printout (http://www.ccc.de/biometrie/images/small_09-attrappe04.jpg?language=en)
In order to fake a fingerprint, one needs an original first. Latent fingerprints are nothing but fat and sweat on touched items. Thus to retrieve someone elses fingerprint (in this case the fingerprint you want to forge) one should rely on well tested forensic research methods. Which is what's to be explained here. (Figure 1).
http://www.ccc.de/biometrie/images/tiny_01-fingerabdruck+mate.jpg
Figure 1: Fat residue from fingerprint (http://www.ccc.de/biometrie/images/small_01-fingerabdruck+mate.jpg?language=en)
A good source of originals for our counterfeits are glasses, doorknobs and glossy paper. The standard method of forensic research makes them visible: Sprinkling it with colored powder, which sticks to the fat (Figure 2).
http://www.ccc.de/biometrie/images/tiny_02-fingerabdruck+grafit.jpg
Figure 2: Visualisation with graphite powder (http://www.ccc.de/biometrie/images/small_02-fingerabdruck+grafit.jpg?language=en)
Another solution involves Cyanoacrylat, the main ingredient of superglue. A small amount thereof is poured into a bottlecap, which is then turned upside down and put over the fingerprint. (Figure 3).
http://www.ccc.de/biometrie/images/tiny_03-mate+deckel.png
Figure 3: Visualisation with superglue (http://www.ccc.de/biometrie/images/small_03-mate+deckel.png?language=en)
The Cyanoacrylat gasses out and reacts with the fat residue to a solid, white substance (Figure 4).
http://www.ccc.de/biometrie/images/tiny_04-finger+zyanoacrylat.png
Figure 4: Print after Cyanacrylate processing (http://www.ccc.de/biometrie/images/small_04-finger+zyanoacrylat.png?language=en)
The further treatment involves scanning/photographing (Figure 5) and a bit of graphical refurbishment (Figure 6).
http://www.ccc.de/biometrie/images/tiny_05-finger+cyanoacrylate+kamera.png
Figure 5: Digitalising the print (http://www.ccc.de/biometrie/images/small_05-finger+cyanoacrylate+kamera.png?language=en)
http://www.ccc.de/biometrie/images/tiny_06-finger+nachbearbeiten.png
Figure 6: Brushing up the image of the print (http://www.ccc.de/biometrie/images/small_06-finger+nachbearbeiten.png?language=en)
The goal is to get an exact image of the fingerprint, for further use as mold, out of which the dummy is made. The easiest way is to print the image on a transparency slide (the ones normally used for an overhead projector) with a laser printer. The toner forms a relief, which is later used similar to letter press printing. Wood glue is suitable for producing the dummy (Figure 7)
http://www.ccc.de/biometrie/images/tiny_07-finger+holzleim.png
Figure 7: Wood glue for the dummy (http://www.ccc.de/biometrie/images/small_07-finger+holzleim.png?language=en)
A small dash of glycerene may be used to optimize humidity and workability. After thorough mixing, the dummy gets coated with a thin layer of the compound (Figure 8,9).
http://www.ccc.de/biometrie/images/tiny_08-attrappe03.jpg
Figure 8: Covering the dummy with wood glue (http://www.ccc.de/biometrie/images/small_08-attrappe03.jpg?language=en)
http://www.ccc.de/biometrie/images/tiny_09-attrappe04.jpg
Figure 9: Glue layer on the printout (http://www.ccc.de/biometrie/images/small_09-attrappe04.jpg?language=en)