Smart sensors, which besides measuring sensor data also process the measured information, are already used in various application scenarios, e.g., in industrial production processes, in smart-home systems, and also in critical infrastructures. Both, industrial applications as well as private applications require that processed data and control signals are protected against unauthorized access and manipulation. It is important to protect the authenticity, integrity, and confidentiality of the measured sensor data as well as the data used to control actuators by means of cryptographic mechanisms, in order to protect sensitive personal information, to protect intellectual property such as configuration parameters, and to prevent damage and harm due to unauthorized manipulations and configurations. The objective of ESPRESSO is to research security technologies for an integration of smart sensors into the Internet of Things (IoT).