Dynamic Physically Unclonable Functions
Wenjie Xiong, André Schaller, Stefan Katzenbeisser, Jakub M. Szefer · 2019
Physical variations in the manufacturing processes of electronic devices have been widely leveraged to design Physically Unclonable Functions (PUFs), which can be used for authentication and key storage. Existing PUFs are static, as their PUF responses remain the same regardless when the PUF is queried. Meanwhile, this paper presents the new concept of Dynamic PUFs, where the responses depend not only on the physical properties of the device but also on the timing of the PUF queries. One application of Dynamic PUFs is in dynamic software-hardware binding, where the control flow of the software can be tied to both the timing of the software and the physical properties of the hardware, in order to protect software execution. This paper presents a realization of Dynamic PUFs using DRAM modules. The evaluation is based on the decay-based DRAM PUFs, which can be realized today and were implemented on commodity devices for testing.