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Education and Innovation in Embedded Systems Design

USI Università della Svizzera italiana, USI Faculty of Informatics, Advanced Learning and Research Institute USI Università della Svizzera italiana USI Faculty of Informatics USI Advanced Learning and Research Institute
TitleEvaluating the Impact of Environmental Factors on Physically Unclonable Functions
Publication TypeConference Paper
Year of Publication2016
AuthorsBellon, S., C. Favi, M. Malek, M. Macchetti, and F. Regazzoni
Conference NameInternational Symposium on Field-Programmable Gate Arrays FPGA 2016
Date Published02/2016
PublisherACM New York, NY, USA
Conference LocationMonterey, CA, USA
ISBN Number978-1-4503-3856-1

Fabrication process introduces some inherent variability to the attributes of transistors (in particular length, widths, oxide thickness). As a result, every chip is physically unique. Physical uniqueness of microelectronics components can be used for multiple security applications. Physically Unclonable Functions (PUFs) are built to extract the physical uniqueness of microelectronics components and make it usable for secure applications.

However, the microelectronics components used by PUFs designs suffer from external, environmental variations that impact the PUF behavior. Variations of temperature gradients during manufacturing can bias the PUF responses. Variations of temperature or thermal noise during PUF operation change the behavior of the circuit, and can introduce errors in PUF responses. Detailed knowledge of the behavior of PUFs operating over various environmental factors is needed to reliably extract and demonstrate uniqueness of the chips.

In this work, we present a detailed and exhaustive analysis of the behavior of two PUF designs, a ring oscillator PUF and a timing path violation PUF. We have implemented both PUFs using FPGA fabricated by Xilinx, and analyzed their behavior while varying temperature and supply voltage. Our experiments quantify the robustness of each design, demonstrate their sensitivity to temperature and show the impact which supply voltage has on the uniqueness of the analyzed PUFs.