The joint project 'sensIC' aims to integrate printed electronics and silicon components directly into products in order to safeguard sensors. To this end, researchers at the Karlsruhe Institute of Technology (KIT) are developing a central component: printed safety circuits with special hardware-based functions, so-called Physical Unclonable Functions (PUFs).

Electronic sensors can reduce costs, improve reliability and enable new functions in many applications. For example, they monitor the temperature of batteries in electrically powered vehicles in order to optimize their service life and performance, and in chemical and pharmaceutical plants they monitor the operating status of passive components in order to detect faults immediately. Their use is particularly important when substances such as drinking water or food, oil or gas are transported through pipelines and a reliable supply and distribution chain must be guaranteed. Sensors can help to detect tampering immediately. However, sensors that convert physical states into data streams are themselves exposed targets for attacks and falsification. "Currently, information security in these applications is mainly based on software algorithms. But no software is perfect. That's why we also have to ensure security via the hardware," explains Professor Jasmin Aghassi-Hagmann, head of the 'Low Power Electronics with Advanced Materials' research group at the Institute of 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 joint project 'Unique identifiability for trustworthy hybrid sensor electronics using additive manufacturing - senslC' combines additively manufactured, i.e. printed, electronics with silicon components and securely integrates them directly into products. As a concrete 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 led by Professor Jasmin Aghassi-Hagmann are developing and manufacturing a central component for this: printed security circuits with so-called Physical Unclonable Functions (PUFs).
PUFs are hardware-based functions that arise due to minute fluctuations in the production process. For example, variations occur in printed electronics due to the coarse print resolution and the materials and inks used. A PUF evaluates these fluctuations and generates an individual signal that acts as a digital fingerprint, so to speak, and enables the unique identification of the component or the secure encryption of information. In a paper recently published in the journal Nature Communications, the research groups led by Professor Mehdi Tahoori, Professor Horst Hahn and Professor Jasmin Aghassi at KIT, together with Professor Axel Sikora's group at Offenburg University of Applied Sciences, have presented a hybrid PUF based on metal oxide thin-film devices that combines printed electronics and silicon technology. This PUF is suitable for securing devices and protecting data in the Internet of Things, in which people communicate with machines and machines communicate with each other.

For industrial and automotive applications, the sensIC project supplements PUFs as electronic identification features with optical identification features developed by Polysecure: embedded fluorescent particles form random and therefore non-copyable patterns as a result of the process. These particle patterns are registered during the production process and allow the component to be uniquely identified as well as providing additional pad protection against hardware manipulation.

The Federal Ministry of Education and Research (BMBF) is funding the three-year sensIC project, which was launched on 1 May 2021, with 2.9 million euros and a total project volume of 4.25 million euros as part of the 'Microelectronics from Germany - Innovation Drivers of Digitalization' framework programme. Benecke-Kaliko, a subsidiary of Continental, is acting as coordinator. In addition to the Institute of Nanotechnology at KIT, other partners involved in the project are Cyient, Polysecure, the Leibniz Institute for New Materials, Offenburg University of Applied Sciences, ContiTech MGW and, as an associated partner, Elmos Semiconductor.