Engineering On-Chip Thermal Effects

Temperature effects can be used to maliciously affect the behavior of digital crypto-circuits. For example, temperature effects can create covert communication channels, and they can affect the stability of physical unclonable functions (PUFs). This talk observes that these thermal effects can be engineered, and we describe two techniques. The first technique shows how to filter the information through a covert temperature channel. This leads to detectors for very specific events, for example, someone touching the chip package. The second technique shows how to mitigate the impact of temperature on a PUF design while avoiding costly post-processing. We discuss the design of a compact ring-oscillator PUF for FPGA which is tolerant to temperature variations