Spin–orbit torque-based reconfigurable physically unclonable functions

The spin torque effects discovered in spintronics have a broad prospect for applications in information memory and logic devices, wherein deterministic switching is highly desired. Variations between devices originating from the fabrication process and inherently random physical features are detrimental to memory and logic devices; however, they are potential entropy sources for hardware security primitives. Here, we demonstrate two types of spin–orbit torque (SOT)-based reconfigurable physically unclonable functions (rPUFs) that are based on process-induced SOT switching current variations and SOT-induced domain wall (DW) nonlinear dynamics, respectively. The experimental results show that both rPUFs have excellent performance in terms of reliability and uniqueness, and the performance is sustained after reconfiguring. Furthermore, the DW nonlinear dynamics-based rPUF can be reconfigured for an unlimited number of times with high uniformity. We believe that our work paves a way for information security and expands the application fields of spintronics.