Dynamic Cryptography through Plasmon‐Enhanced Fluorescence Blinking
Yongfeng Lu, Hongrui Cheng, Guang‐Can Li, Fei Han, Cheng Jiang, Tsz Wing Lo, Dangyuan Lei, Paul S. Francis, Yuanhui Zheng
Abstract
Abstract 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.