Magnetic Unclonable Functions Leveraging Remanence and Anhysteretic States

Year: 2025

Authors: Magni A., Barrera G., Celegato F., Riboli F., Wiersma D.S., Nocentini S., Tiberto P.

Autors Affiliation: Ist Nazl Ric Metrol, Str Cacce 91, I-10135 Turin, Italy; CNR, Ist Nazl Ott, Via N Carrara 1, I-50019 Sesto Fiorentino, Firenze, Italy; Univ Firenze, European Lab Nonlinear Spect LENS, Dipartimento Fis, Via G Sansone 1, I-50019 Sesto Fiorentino, Firenze, Italy.

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.

Journal/Review: ADVANCED FUNCTIONAL MATERIALS

More Information: Part of this work was carried out at Nanofacility Piemonte, a labora-tory supported by the Compagnia di San Paolo Foundation, and atQR Lab – Micro&Nanolaboratories, INRiM. This work was partially sup-ported by project SERICS (PE00000014) under the MUR National Recoveryand Resilience Plan funded by the European Union-NextGenerationEUand co-funded by the European Union-NextGenerationEU, Integratedinfrastructure initiative in Photonic and Quantum Sciences-I-PHOQS(IR0000016, ID D2B8D520, CUP B53C22001750006). S.N. acknowledgesthe financial support from project PRIN 2022 2022T3B4HS-PE11 – Multi-step optical encoding in anticounterfeiting photonic tags based on liq-uid crystals (PHOTAG) financed in the framework of Piano Nazionaledi Ripresa e Resilienza (PN RR). G.B. acknowledges the financial sup-port from project PRIN 2022WY522H- PE3-10 – Fast readable label byUnique Magnetic Fingerprints on Industry 4.0: polymeric nanocompos-ites for a global exchange of information with a high level of security (U-MagFinger) financed in the framework of Piano Nazionale di Ripresa eResilienza (PNRR).
KeyWords: magnetic microstructures; physical unclonable functions; reconfigurability; robustness; unpredictable magnetic properties
DOI: 10.1002/adfm.202516376