  The Internet of Things (IoT) is considered as the key enabling technology for
smart services. Security and privacy are particularly open challenges for IoT
applications due to the widespread use of commodity devices. This work
introduces two hardware-based lightweight security mechanisms to ensure sensed
data trustworthiness (i.e., sensed data protection and sensor node protection)
and usage privacy of the sensors (i.e., privacy-aware reporting of the sensed
data) for centralized and decentralized IoT applications. Physically unclonable
functions (PUF) form the basis of both proposed mechanisms. To demonstrate the
feasibility of our PUF-based approach, we have implemented and evaluated PUFs
on three platforms (Atmel 8-bit MCU, ARM Cortex M4 32 bit MCU, and Zynq7010
SoC) with varying complexities. We have also implemented our trusted sensing
and privacy-aware reporting scheme (for centralized applications) and secure
node scheme (for decentralized applications) on a visual sensor node comprising
an OV5642 image sensor and a Zynq7010 SoC. Our experimental evaluation shows a
low overhead wrt.~latency, storage, hardware, and communication incurred by our
security mechanisms.
