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.　©　2022　Wiley-VCH　GmbH.