Dynamic Cryptography through Plasmon-Enhanced Fluorescence Blinking

Merging cryptographic primitive technologies and physical unclonable functions (PUFs) have become a new paradigm of one-way encryption. Herein, the authors report a dynamic PUF cryptographic primitive based on plasmonic fluorescence blinking from single or a few dye molecules embedded within the nanogaps of plasmonic patch nanoantennas. This cryptographic primitive carries two sets of high-capacity optical codes: the fluorescence blinking of the embedded dye molecules and multi-color light scattering enabled by the plasmonic nanoantennas. The former allows the generation of temporal binary codes from a large number of individual plasmonic patch nanoantennas by holding either 1 (bright state) or 0 (dark state), while the latter provides a permanent color-based novenary code that acts as a decryption channel for authentication. Benefiting from the high electromagnetic field localized within the nanogaps and the large Purcell enhancement of the plasmonic nanoantennas, the fluorescence blinking is readily detectable by a common fluorescence microscope with a mercury arc lamp as a low-power excitation source. The developed dynamic PUF codes are robustly and accurately authenticated by a self-programmed computer vision algorithm. This study revolutionizes the conventional static PUF encryption to nanophotonics-based dynamic encryption, opening a new avenue for next-generation advanced anti-counterfeiting.

Automated summary

This study presents a dynamic PUF cryptographic primitive based on plasmonic fluorescence blinking, which utilizes high-capacity optical codes and color codes for decryption and authentication. The fluorescence blinking is detectable by a common fluorescence microscope due to the high electromagnetic field localized within the nanogaps and the large Purcell enhancement.