Magnetic Unclonable Functions Leveraging Remanence and Anhysteretic States

Abstract Physical Unclonable Functions (PUFs), derived from the unique properties of physical hardware, enable the generation of cryptographic keys with enhanced security against cloning and cyber‐attacks because of their inherent randomness and on‐the‐fly key extraction. The scientific interest on these systems motivated the exploration of several hardware from optical, memristive to electric. Compared to optical and electric systems, magnetic PUFs offer strong robustness against environmental perturbations and easy integration into micro‐devices because of their compatibility with CMOS‐technology. A new magnetic platform is introduced that allows password generation with over 400 independent bits with a dual‐mode operation. A deterministic mode provides a stable, repeatable response to a given interrogation, while a reconfigurable mode ensures a different response each time. This system utilizes nominally identical FeGa dot array that, given their microscopic magnetic properties, are hard to clone with current technology. This enables the extraction of highly entropic cryptographic keys via the Magneto‐Optical Kerr Effect microscopy. Moreover, magnetic field‐controlled key generation enables the dynamic switching between deterministic and reconfigurable key generation within the same hardware without need for multiple interrogation stimuli. This dual functionality enhances security and flexibility, opening new avenues for secure and adaptable cryptographic implementations in anti‐counterfeiting and secure password generation.