Researchers from the Fraunhofer organisation in Germany have become the latest group to develop this method of protecting electronic components from multiple kinds of copying.
The technology could work for components found in plant engineering equipment, as well as chips on access cards such as for subscription TV services.
This could help tackle a counterfeiting problem that cost the German mechanical engineering sector €6.4bn (£5.4bn) last year, according to the German Engineering Federation (VDMA).
The team plans to unveil a prototype device at the Embedded World exhibition and conference in Nuremberg next month, following in the footsteps of Philips Research spin-out company Intrinsic ID, which is producing a similar technology.
‘At the moment the problem is you have specific counter-measures to protect against single attacks. It’s not a holistic approach,’ Dominik Merli, one of the scientists from the Fraunhofer Institute for Secure Information Technology, told The Engineer.
‘The other problem is if you have a key inside a device, it is stored in some way and maybe someone can extract it or read the key. The advantage of our system is the key is not present in the device. The secret is in the structure of the chip.’
The idea behind the technology, known as a physical unclonable function (PUF), is to scan the chip and generate a digital encryption key based on the tiny unique differences in thickness and density of the component materials.
The key would not be saved electronically and so could not be copied or intercepted from the chip using scanning electron microscopes, focused ion beams or laser bolts. Invasive attacks would damage the structure of the device and therefore alter the key.
Once generated, the key could be checked against the manufacturer’s database to prove it is genuine, or it can be used to generate a second, public key that also authenticates the equipment.
Several types of PUF have been outlined since the idea was first proposed in 2002. The Fraunhofer team’s PUF is a ring oscillator, which sends an electronic signal around the chip in a circular motion.
Disruptions to the signal’s speed and frequency indicate changes of thickness and density in the chip’s structure. The next step is developing the method of creating the digital key.
Merli said he imagined the technology could have widespread uses outside the engineering sector.
‘The first commercial models [of this kind of technology] are available but they’re for very specific uses in high-security products,’ he said.
‘But because this technology is not directed at specific attacks, it could maybe replace some other things and become affordable in consumer products.’