Fig. 1: Artificial fingerprints as physical unclonable functions for authentication and identification.

a Graphical workflow of authentication and identification processes through fingerprints. b Product’s identification/authentication through artificial fingerprints. The artificial fingerprint can be physically transferred on the surface of the product by the manufacturer right after its production and subsequently registered and stored in the database. The product is then delivered to the buyer and the identification/authentication of the product can be performed directly by the end user by comparing the artificial fingerprint with fingerprints stored in the database. c Schematics of fabrication procedure by BCP self-assembly and pattern transfer for the realization of artificial nano fingerprints. d SEM images of self-assembled lamellar BCPs in typical fingerprint pattern-like and nanoscale defects on Si substrate. e Typical defects of lamellar BCPs: positive and negative phase terminal points (yellow and light blue circles, respectively), positive and negative phase 3-way junctions (orange and blue triangles, respectively), positive and negative phase dots (violet and light green squared off dots, respectively). Pattern transfer of artificial nanofingerprints on diverse surfaces, including (f) diamond, (g) Si, (h) quartz, and (i) SiO₂ (object images are to be considered for demonstration purposes of the items in which the engraving process can be applied to). All scale bars are set to 200 nm.