New technique for document fingerprinting can cheaply detect forgery

Researchers have developed a technique to identify the unique ‘fingerprints’ of any paper document based on the composition of the paper.

Although some official documents can be converted to a digital form, it is impossible to do away with paper altogether – and up to now it has proven complicated and expensive to protect such official paper documents from forgery. One method is to embed an RFID chip into the document, although tamper-proof RFID chips have proven to be too expensive for everyday use. Now, a team of researchers at Newcastle University have devised a cheap and easy-to-use method for preventing forgery of paper documents by using an ordinary camera to create a unique digital fingerprint of the document.

The researchers took a different approach. Paper is composed of random patterns of interwoven wooden and fiber particles. By analysing these patters, the researchers realized that it was possible to capture and digitize this unique ‘texture’ fingerprint with an ordinary camera. They then wrote an algorithm which would use the photo to generate an identifier for each sheet of paper, and convert this into a barcode which could be checked by anyone. To produce a forgery would require the forger to duplicate the random interweaving of the particles in the paper – an impossibility. This method has been demonstrated to be 100 percent accurate at identifying a forgery – even if the paper has been singed, soaked in water and scrumpled up in a pocket.

Dr Feng Hao, one of the researchers involved and Reader in Security Engineering at Newcastle University, explained: “What we have shown is that every piece of paper contains unique intrinsic features just as every person has unique intrinsic biometric features. By using an ordinary light source and an off-the-shelf camera, it takes just 1.3 seconds and one snapshot to capture those features and produce a texture ‘fingerprint’ that is unique to that document.”

The technique can be used with any paper document. For example, before issuing a university degree certificate, a picture would be taken of the certificate paper and converted to a barcode, which would then be printed on the certificate. Anyone wanting to verify the authenticity of the certificate would take a picture of the certificate presented to them and compare the new image with the authentic copy stored in the barcode. What other types of forgery might be prevented with this system?