MIT researchers have created a microscopic, low-cost cryptographic ID tag, designed to protect products from counterfeiting by providing improved security compared to traditional radio frequency tags (RFIDs). The technology, developed using terahertz waves, can offer a highly secure, low-cost, and easy-to-implement solution in preventing tampering and ensuring product authenticity.
RFID tags typically use radio waves to secure products. But, because these tags can be peeled off a product and reattached to a counterfeit one, they have a significant security vulnerability. The MIT team addressed this by developing an antitampering tag that utilises terahertz waves, which are smaller and have higher frequencies than radio waves.
To create the tags, microscopic metal particles are mixed with the adhesive that attaches the tag to the product. Terahertz waves are then used to detect the random pattern formed by these particles on the product’s surface, forming a unique identifier similar to a fingerprint for each item.
“As long as the glue interface is destroyed by a counterfeiter, these responses are impossible to duplicate,” says Ruonan Han, one of the researchers. This system ensures that if a tag is tampered with, the unique glue pattern, and hence the item’s authenticity, will be destroyed.
However, the researchers were confronted with a significant challenge while testing the antitampering tag: accurately measuring if two glue patterns matched. To overcome this, they created a machine-learning model that compares glue patterns and calculates their similarity with over 99% precision.
Despite the system’s strength, there are limitations to the current model. Terahertz waves experience high levels of loss during transmission which restricts the sensor from being more than 4 centimeters from the tag. Additionally, the angle between the sensor and the tag must be less than 10 degrees to avoid degradation. The team aims to address these limitations in future research.
“This application can go beyond broadband wireless, you can use terahertz for ID, security, and authentication,” adds Han. Following this development, they hope other researchers will be inspired to explore deeper into the vast potential of terahertz wave applications.
Their work was supported by the U.S. National Science Foundation and the Korea Foundation for Advanced Studies. The team’s methodology and findings will be presented at the forthcoming IEEE Solid State Circuits Conference.
