(Source: Newcastle University)(Source: Newcastle University)

In an effort to prevent forgery, scientists from Newcastle University, UK, have discovered a cost-effective way to authenticate any paper document by capturing it with a picture taken from a standard camera.

Researchers were able to identify a unique ‘texture’ fingerprint by analyzing translucent patterns by shining a light through paper.

Using a standard camera, researchers captured the random interweaving of wooden particles showing a unique fingerprinting code that can be captured and verified with 100 percent accuracy. Additionally, researchers demonstrated that the process continues to be reliable even if the paper is crumpled, soaked, heated or scribbled on.

Dr. Feng Hao, co-author and Reader in Security Engineering at Newcastle University, said:

"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.

"Cloning the paper document would require reproducing the same random interweaving of the wooden particles in the paper — which is impossible, massively reducing the possibility of forgery."

The problem of securing documents is nothing new considering that paper continues to be the most common means of proving authenticity (receipts, contracts, passports, certificates).

Embedding electronics such as RFID chips within documents is one solution to protect against fraud, but it is a costly process.

Researchers are looking to paper for not only the reduction in cost, but also because each individual sheet of paper is unique.

"Typically, wooden particles are used as the base and multiple substances are used to stick these particles together," explains lead author Ehsan Toreini, a PhD student in Cyber Security in Newcastle University's School of Computing Science.

"Our idea was that the majority of paper used for official and legal documents, certificates, invoices and so on is not completely opaque. Different types let through different levels of light and reflect it in different ways and as a result, each one reveals a unique fingerprint."

"We proposed an algorithm that generates a compact and unique identifier for each sheet of paper. This identifier is then converted into a QR code, which can be verified efficiently off-line by anyone."

"Since this identifier is basically representative of that paper texture, any illegal modifications — including copying the contents of the document to another paper sheet — could be identified."

Making each paper sample (fingerprint) consistent, the team used a 37 millimeter-by-57 millimeter rectangular box, asking users to only capture what was inside the box with the camera.

"Our algorithm recognizes this box automatically and the texture patterns inside this area are analysed for the fingerprint. We only need one sample from this area to construct its fingerprint," says Mr Toreini.

Researchers believe the technique will prevent counterfeiting of any paper-made physical documents.

The research is published in the academic journal ACM Transactions on Information and System Security.