In a bid to tackle the problem of item counterfeiting, researchers at MIT have taken a significant step forward in developing a microscopic, cheap and secure cryptographic ID tag. This tiny tag, which uses terahertz waves and is notably smaller, less expensive, and safer than conventional radio frequency tags (RFIDs), was initially found to have a significant flaw that counterfeiters could exploit – the tag could be removed from an original item and placed onto a fake one without detection.
The MIT team, however, has now addressed this security vulnerability by developing an antitampering ID tag. This is achieved by adding microscopic metal particles to the glue that fixes the tag to the item. The terahertz waves are then used to detect the unique pattern formed by these particles on the item’s surface. This pattern is as unique to each item as a fingerprint, providing a robust method of authenticating items, explains Eunseok Lee, an MIT graduate student.
The process works by the metal particles effectively acting as mirrors for the terahertz waves. Unique reflected patterns are created depending on the size, location, and orientation of the mirrors. Peeling the chip from the item destroys this unique pattern, thereby indicating a counterfeit item, as professed by Associate Professor Ruonan Han.
The team’s findings, set to be presented at the IEEE Solid State Circuits Conference, highlight their development of a 4 square millimeter light-powered antitampering tag. Importantly, a machine-learning model was also demonstrated that confirms the potential for detecting tampering through identification of similar glue patter “fingerprints” with over 99% accuracy.
The cheap and tiny size of this advanced tag presents vast opportunities for widespread adoption within large supply chains, and particularly useful in sectors wherein items are too small for a traditional RFID, such as specific medical devices.
One of the project’s main areas of focus was to authenticate the items themselves rather than just the attached tag. As such, the developed tag contains a series of minute slots for terahertz waves to pass through, therefore hitting the microscopic metal particles mixed in the glue and reflected back to a receiver to authenticate the item.
To maintain the system’s robustness, vendors would take an initial reading of the antitampering tag once attached to an item, storing the data in the cloud for future verification.
However, the team encountered an issue when testing due to the laborious and time-consuming process needed to establish if two glued patterns match. To streamline this, a machine-learning model was developed, resulting in the accurate calculation of pattern similarity in over 99% of instances.
This authentication system does face some challenges such as the need for a close proximity between the sensor and the tag, and a specific angle between the two for accurate readings. Nevertheless, the team aims to address these hurdles and remains optimistic about the capabilities and possibilities of using terahertz waves, despite the technical challenges, Han concludes.
The research project was supported in part by the U.S. National Science Foundation and the Korea Foundation for Advanced Studies.
