At a quick glance, a sheet of paper may seem very uniform and much like all others. Look closer, however, and you'll see that it's made up of a random jumble of tiny interwoven wood particles. Scientists from Newcastle University have taken advantage of that fact, using each jumble as a unique "texture fingerprint" for inexpensively authenticating individual paper items such as bank notes, passports or legal documents.

Users wishing to check a paper start by simply holding it up against a regular light source (so the light partially shines through it from behind), then using a conventional digital camera to take a close-up photo of one section of it – that area is already indicated with a small rectangular box printed on the paper.

There's also a QR code on the paper, which they read with their smartphone. That code contains information on exactly what the unreproducible wood particle pattern within the box should look like, if the paper is indeed the original. Using a computer program, users can check if the pattern shot by their camera matches the pattern described in the code.

Of course, although the QR code would be easy enough to photocopy along with the rest of the paper's contents, the wood particle pattern of that copy would no longer be a match.

The system has reportedly been tested and verified 100 percent accurate, and it works even if the paper has been crumpled, soaked or scribbled upon.

The research was conducted by PhD student Ehsan Toreini, Dr. Feng Hao and Dr. Siamak Shahandashti.