Inductive sensor with integrated components

Abstract:
In today's world, the requirement for data security in electronics is constantly increasing and is becoming more and more important not only in the industry, but also in other areas, such as the medical sector. Electronic hardware, such as cell phones or communication modules used in the energy sector, collect sensitive data from consumers and must be protected by adapted algorithms. In addition, the risk of product piracy or reverse engineering attempts has increased in recent years due to the rise of digitalization and requires appropriate counter measures. Algorithms must be constantly adapted to the new security challenges. In addition, purely software-based protection has long been insufficient to protect sensitive electronics. Much better protection against possible cyber-attacks is offered by a combination of software and physical hardware protection. There are various ways of achieving this, such as encapsulation with potting material (epoxy resin) or wrapping with a drill protection film. In the BMBF project "Safe" the possibility was investigated of integrating standardized components into the printed circuit board (PCB), the so called embedding technology. The embedding, not only serves to protect against external influences such as moisture, dirt, etc., but can also counteract reverse engineering attempts. It is more difficult for the potential attacker to draw conclusions about the internal structures of the circuit. In addition, a "protective shield" in the form of an integrated rectangular planar coil was developed for the outer layers. This is additionally connected along all edges of the module by further contacts. This makes it possible to detect physical attacks that occur from the side or above. The goal is to delete the data or digital keys in the event of a potential attack in order to keep them secret or prevent tampering. In experiments, the inductance of the system was monitored by an integrated circuit (Texas Instruments LDC131x Series) to detect the approach of electrically conductive objects. These generate eddy currents on the surface, whose magnetic fields counteract the current of the induction coil, reducing the inductance of the system and increasing the resonant frequency of the sensor. These characteristics of these changes can then be evaluated and assigned to specific attack scenarios.