‘Unclonable’ tag proposed to fight counterfeit goods

Researchers claim to have created an unclonable tag that can never be replicated, even by the manufacturer, and could be used to protect goods from counterfeiting.

Riikka Arppe-Tabbara, Mohammad Tabbara and Thomas Just Sørensen of the University of Copenhagen in Denmark describe in the journal ACS Applied Materials & Interfaces how they created an authentication system using physical unclonable functions (PUFs) – tags based on random processes that are impossible to replicate.

As they explain in their report, an example of a PUF would be throwing a handful of sand on a surface. Each throw generates a random pattern that cannot be copied. The tags used in their study were created using commercial printing and coating technologies using several combinations of carrier materials and taggant materials.

The team laser-printed QR codes on paper and then sprayed the PUF pattern on the surface. The PUF inks contained microparticles, which formed random patterns that showed up as white spots on a black background when magnified.

To validate their system, they then generated 10,000 tags and imaged them with a smart phone camera to establish a registry. Then, they re-imaged the tags with different smart phone readers and tried to match them to the registry. The system correctly identified 76 per cent of the PUF tags.

None of the tags were identified incorrectly, but some codes that were dirty or out-of-focus required an additional scan. The researchers estimate that the system can generate 2.5 × 10120 unique codes with a low cost of manufacture.