  A unique set of characteristics are packed in emerging nonvolatile
reduction-oxidation (redox)-based resistive switching memories (ReRAMs) such as
their underlying stochastic switching processes alongside their intrinsic
highly nonlinear current-voltage characteristic, which in addition to known
nano-fabrication process variation make them a promising candidate for the next
generation of low-cost, low-power, tiny and secure Physically Unclonable
Functions (PUFs). This paper takes advantage of this otherwise disadvantageous
ReRAM feature using a combination of novel architectural and peripheral
circuitry. We present a physical one-way function, nonlinear resistive Physical
Unclonable Function (nrPUF), potentially applicable in variety of
cyber-physical security applications given its performance characteristics. We
experimentally verified performance of Valency Change Mechanism (VCM)-based
ReRAM in nano-fabricated crossbar arrays across multiple dies and runs. In
addition to a massive pool of Challenge-Response Pairs (CRPs), using a
combination of experimental and simulation, our proposed PUF shows a
reliability of 98.67%, a uniqueness of 49.85%, a diffuseness of 49.86%, a
uniformity of 47.28%, and a bit-aliasing of 47.48%.
