MIT unveils battery-free crypto tag for anti-counterfeit

MIT researchers have developed a battery-free cryptographic ID tag that’s small enough to fit on virtually any product and verify its authenticity.

The millimetre-sized ID chip includes a cryptographic processor, an antenna array that transmits data in the high terahertz range, and photovoltaic diodes for power, say the researchers behind the project.

The device cost a few cents each and could be used to authenticate nearly any product to help combat losses to counterfeiting, they suggest. Early applications could be the semiconductor industry, which loses $7bn to $10bn a year to counterfeit silicon chips.

Wireless ID tags are becoming increasingly popular for authenticating goods as they change hands in the supply chain, but they come with size, cost, energy, and security trade-offs that limit their potential, according to the MIT team.

For instance, RFID tags are often too large to fit on smaller objects such as medical and industrial components, automotive parts, or silicon chip, and on the whole lack tough security measures. Some have encryption schemes to protect against cloning and ward off hackers, but these tend to be large and power hungry.

The new ‘tag of everything’ device was presented at the IEEE International Solid-State Circuits Conference (ISSCC) by Ruonan Han, an associate professor in the Department of Electrical Engineering and Computer Science at MIT.

“If I want to track the logistics of, say, a single bolt or tooth implant or silicon chip, current RFID tags don’t enable that,” he said.

“We built a low-cost, tiny chip without packaging, batteries, or other external components, that stores and transmits sensitive data.”

The researchers started designing the tags with three main objectives: doing away with packaging that increases bulk; using high terahertz frequencies that allow communication over longer distances; and building in cryptographic protocols.

The latter distinguishes them from RFID tags, which “can be scanned by essentially any reader and transmit their data indiscriminately.”

To make it battery-free, they incorporated tiny holes in the antennas that allow light from the reader to pass through to photodiodes underneath that convert the light into about 1 volt of electricity. In time, the aim is to power the chip through the terahertz signals themselves, which would mean the photodiodes aren’t necessary.

At the moment the tags can be read from a distance of around 5cm using a scanner, but the intention is to extend that range.