Product counterfeiters are increasingly targeting chips and electronic components, with attacks on hardware modules becoming commonplace. Tailor-made security technology utilizes a component‘s individual material properties to generate a digital key. This provides components with an identity, since their unique structure cannot be copied. At this year’s embedded world Exhibition and Conference, researchers from the Fraunhofer Institute for Secure Information Technology SIT will be demonstrating how electronic components or chips can be made counterfeit-proof using physical unclonable functions (PUFs). “Every component has a kind of individual fingerprint since small differences inevitably arise between components during production,” said Dominik Merli, a scientist at Fraunhofer SIT in Garching. Printed circuits, for instance, end up with minimal variations in thickness or length during the manufacturing process. While these variations do not affect functionality, they can be used to generate a unique code. A PUF module is integrated directly into a chip, a setup that is feasible not only in a large number of programmable semiconductors known as FPGAs (field programmable gate arrays) but equally in hardware components such as microchips and smartcards. “At its heart is a measuring circuit, for instance a ring oscillator. This oscillator generates a characteristic clock signal which allows the chip‘s precise material properties to be determined. Special electronic circuits then read these measurement data and generate the component-specific key from the data”, explains Merli. Unlike conventional cryptographic processes, the secret key is not stored on the hardware but is regenerated as and when required. Since the code relates directly to the system properties at any given point in time, it is virtually impossible to extract and clone it. Invasive attacks on the chip would alter physical parameters, thus distorting or destroying the unique structure. The Garching-based researchers have already developed two prototypes: A butterfly PUF and a ring oscillator PUF. At present, these modules are being optimized for practical applications.
How long until this counterfeit measure is broken? Not long, I'm sure.