Printed circuits protect sensors

Joint project “sensIC” links materials science and cybersecurity - PUFs function as electronic identification features

PUF core for the unique identification of a component or the secure encryption of information. (Photo: Alexander Scholz, HS Offenburg and KIT)

PUF core for the unique identification of a component or the secure encryption of information. (Photo: Alexander Scholz, HS Offenburg and KIT)

Electronic sensors can benefit many industrial applications, such as automotive engineering. But they have to be protected from attacks and falsifications. The new joint project "sensIC" aims to integrate printed electronics and silicon components directly into products in order to secure sensors. At the Karlsruhe Institute of Technology (KIT), researchers are developing a central component for this: printed safety circuits with special hardware-based functions, so-called Physical Unclonable Functions (PUFs). The Federal Ministry of Research is funding sensIC with a total of 2.9 million euros. The industrial partners are investing a further 1.35 million euros in the project.

In electrically powered vehicles, they monitor the temperature of the batteries in order to optimize their service life and performance; in plants in the chemical and pharmaceutical industries, they monitor the operating status of passive components in order to detect errors immediately: Electronic sensors can reduce costs and improve reliability in many applications and enable new functions. Their use is particularly important when substances such as drinking water or food, oil or gas are transported through pipelines and a trustworthy supply and distribution chain must be guaranteed. Sensors can help to detect manipulations immediately. However, sensors that convert physical states into data streams are themselves exposed targets for attacks and falsifications. How can sensors and sensor data be effectively protected? “Information security in these applications is currently based primarily on software algorithms. But no software is perfect. Therefore, we also have to ensure safety with the hardware, ”explains Professor Jasmin Aghassi-Hagmann, head of the research group“ Low Power Electronics with Advanced Materials ”at the Institute for Nanotechnology (INT) at KIT. “Additive processes that create two- and three-dimensional components layer by layer are particularly suitable for this. With the help of such components, we can retrofit safety functions without having to hand over the design to the manufacturer. " Therefore, we also have to ensure safety with the hardware, ”explains Professor Jasmin Aghassi-Hagmann, head of the research group“ Low Power Electronics with Advanced Materials ”at the Institute for Nanotechnology (INT) at KIT. “Additive processes that create two- and three-dimensional components layer by layer are particularly suitable for this. With the help of such components, we can retrofit safety functions without having to hand over the design to the manufacturer. " Therefore, we also have to ensure safety with the hardware, ”explains Professor Jasmin Aghassi-Hagmann, head of the research group“ Low Power Electronics with Advanced Materials ”at the Institute for Nanotechnology (INT) at KIT. “Additive processes that create two- and three-dimensional components layer by layer are particularly suitable for this. With the help of such components, we can retrofit safety functions without having to hand over the design to the manufacturer. "
 
The new joint project "Clear identifiability for trustworthy hybrid sensor electronics with the help of additive manufacturing - senslC" combines additively manufactured, i.e. printed electronics with silicon components and securely integrates them directly into products. As a specific application of the project, hybrid integrated sensor circuits are built into hoses, as required for various automotive and industrial applications. The project, coordinated by Benecke-Kaliko, a subsidiary of Continental, combines materials science and cybersecurity. At INT, researchers working with Professor Jasmin Aghassi-Hagmann are developing and manufacturing a central component for this purpose: printed safety circuits with so-called Physical Unclonable Functions (PUFs).

Digital fingerprint enables identification and encryption

PUFs are hardware-based functions that arise due to the smallest fluctuations in the production process. In printed electronics, for example, there are variations due to the coarse print resolution and the materials and inks used. A PUF evaluates these fluctuations and uses them to generate an individual signal that acts as a digital fingerprint, so to speak, and enables the component to be clearly identified or information to be encrypted securely. In a recently published publication in the journal Nature Communications, scientists from KIT and the Offenburg University of Applied Sciences presented a hybrid PUF based on metal oxide thin-film components that combines printed electronics and silicon technology. This PUF is suitable for
 
The sensIC project supplements the PUFs as electronic identification features for applications in industry and automotive with optical identification features, developed by the company Polysecure: Embedded fluorescent particles form random and therefore non-copiable patterns due to the process. These particle patterns are registered during the production process and allow the component to be clearly identified as well as additional tamper protection against hardware manipulation.


Original publication (Open Access)

Alexander Scholz, Lukas Zimmermann, Ulrich Gengenbach, Liane Koker, Zehua Chen, Horst Hahn, Axel Sikora, Mehdi B. Tahoori & Jasmin Aghassi-Hagmann: Hybrid low-voltage physical unclonable function based on inkjet-printed metal- oxide transistors. Nature Communications. Nature Research, 2020. DOI: 10.1038 / s41467-020-19324-5
https://www.nature.com/articles/s41467-020-19324-5

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