A number of years in the past, MIT researchers invented a cryptographic ID tag that’s a number of occasions smaller and considerably cheaper than the standard radio frequency tags (RFIDs) which might be usually affixed to merchandise to confirm their authenticity.
This tiny tag, which affords improved safety over RFIDs, makes use of terahertz waves, that are smaller and journey a lot quicker than radio waves. But this terahertz tag shared a serious safety vulnerability with conventional RFIDs: A counterfeiter may peel the tag off a real merchandise and reattach it to a pretend, and the authentication system could be none the wiser.
The researchers have now surmounted this safety vulnerability by leveraging terahertz waves to develop an antitampering ID tag that also affords the advantages of being tiny, low cost, and safe.
They combine microscopic metallic particles into the glue that sticks the tag to an object, after which use terahertz waves to detect the distinctive sample these particles kind on the merchandise’s floor. Akin to a fingerprint, this random glue sample is used to authenticate the merchandise, explains Eunseok Lee, {an electrical} engineering and pc science (EECS) graduate scholar and lead creator of a paper on the antitampering tag.
“These metal particles are essentially like mirrors for terahertz waves. If I spread a bunch of mirror pieces onto a surface and then shine light on that, depending on the orientation, size, and location of those mirrors, I would get a different reflected pattern. But if you peel the chip off and reattach it, you destroy that pattern,” provides Ruonan Han, an affiliate professor in EECS, who leads the Terahertz Integrated Electronics Group within the Research Laboratory of Electronics.
The researchers produced a light-powered antitampering tag that’s about 4 sq. millimeters in measurement. They additionally demonstrated a machine-learning mannequin that helps detect tampering by figuring out related glue sample fingerprints with greater than 99 % accuracy.
Because the terahertz tag is so low cost to supply, it could possibly be carried out all through a large provide chain. And its tiny measurement allows the tag to connect to objects too small for conventional RFIDs, similar to sure medical gadgets.
The paper, which might be introduced on the IEEE Solid State Circuits Conference, is a collaboration between Han’s group and the Energy-Efficient Circuits and Systems Group of Anantha P. Chandrakasan, MIT’s chief innovation and technique officer, dean of the MIT School of Engineering, and the Vannevar Bush Professor of EECS. Co-authors embody EECS graduate college students Xibi Chen, Maitryi Ashok, and Jaeyeon Won.
Preventing tampering
This analysis undertaking was partly impressed by Han’s favourite automobile wash. The enterprise caught an RFID tag onto his windshield to authenticate his automobile wash membership. For added safety, the tag was made out of fragile paper so it will be destroyed if a less-than-honest buyer tried to peel it off and stick it on a distinct windshield.
But that isn’t a really dependable technique to forestall tampering. For occasion, somebody may use an answer to dissolve the glue and safely take away the delicate tag.
Rather than authenticating the tag, a greater safety resolution is to authenticate the merchandise itself, Han says. To obtain this, the researchers focused the glue on the interface between the tag and the merchandise’s floor.
Their antitampering tag incorporates a sequence of miniscule slots that allow terahertz waves to cross by the tag and strike microscopic metallic particles which were blended into the glue.
Terahertz waves are sufficiently small to detect the particles, whereas bigger radio waves wouldn’t have sufficient sensitivity to see them. Also, utilizing terahertz waves with a 1-millimeter wavelength allowed the researchers to make a chip that doesn’t want a bigger, off-chip antenna.
After passing by the tag and placing the item’s floor, terahertz waves are mirrored, or backscattered, to a receiver for authentication. How these waves are backscattered will depend on the distribution of metallic particles that mirror them.
The researchers put a number of slots onto the chip so waves can strike totally different factors on the item’s floor, capturing extra info on the random distribution of particles.
“These responses are impossible to duplicate, as long as the glue interface is destroyed by a counterfeiter,” Han says.
A vendor would take an preliminary studying of the antitampering tag as soon as it was caught onto an merchandise, after which retailer these information within the cloud, utilizing them later for verification.
AI for authentication
But when it got here time to check the antitampering tag, Lee bumped into an issue: It was very tough and time-consuming to take exact sufficient measurements to find out whether or not two glue patterns are a match.
He reached out to a good friend within the MIT Computer Science and Artificial Intelligence Laboratory (CSAIL) and collectively they tackled the issue utilizing AI. They skilled a machine-learning mannequin that might examine glue patterns and calculate their similarity with greater than 99 % accuracy.
“One drawback is that we had a limited data sample for this demonstration, but we could improve the neural network in the future if a large number of these tags were deployed in a supply chain, giving us a lot more data samples,” Lee says.
The authentication system can be restricted by the truth that terahertz waves endure from excessive ranges of loss throughout transmission, so the sensor can solely be about 4 centimeters from the tag to get an correct studying. This distance wouldn’t be a problem for an utility like barcode scanning, however it will be too brief for some potential makes use of, similar to in an automatic freeway toll sales space. Also, the angle between the sensor and tag must be lower than 10 levels or the terahertz sign will degrade an excessive amount of.
They plan to deal with these limitations in future work, and hope to encourage different researchers to be extra optimistic about what may be completed with terahertz waves, regardless of the numerous technical challenges, says Han.
“One thing we really want to show here is that the application of the terahertz spectrum can go well beyond broadband wireless. In this case, you can use terahertz for ID, security, and authentication. There are a lot of possibilities out there,” he provides.
This work is supported, partially, by the U.S. National Science Foundation and the Korea Foundation for Advanced Studies.