Design and optimization of a strong PUF exploiting sneak paths in resistive cross-point array

In this paper, we propose a novel design of strong Physical Unclonable Function (PUF) leveraging the sneak paths in the resistive cross-point (X-point) array for device authentication. The entanglement of the sneak paths in the X-point array greatly enhances the entropy of the physical system, thereby increasing the space of challenge-response pairs (CRPs). “Digital” resistance distribution in X-point array is employed to eliminate the undesired collision or diffuseness when “analog” resistance distribution is used. The X-point PUF's characteristics are evaluated on the 128×128 cross-point arrays by SPICE simulation. The simulation results show that the on-state resistance (Ron) activity affects the PUF's performance and 4% is shown as an optimized design in terms of large reference current (Iref) tolerance range. In addition, the X-point PUF presents no correlation between challenges and responses, showing improved security.