Comprehensive Analysis of Supply Voltage Watermarking for Protection of Sensor Systems

Abstract

Securing smart sensors in IoT or more general in automation applications is mostly seen and addressed from a networking viewpoint. While there is much research on how to make communication in sensor networks secure and prevent data manipulation during transmission, less attention is paid to the sensor itself that provides the actual measurement data. However, manipulation of the sensor can lead to serious malfunction of an automation system. Protection of the hardware side of a sensor is therefore desirable, but faces constraints related to cost or technical feasibility. In this paper, we investigate a simple watermarking scheme applied to the analog readout of a resistive sensor. Based on the example of a outside temperature sensor in a heating control, we analyze various attack scenarios involving voltage injection and determine the level of protection that can be achieved.