An unclonable plasmonic anti-counterfeiting strategy is demonstrated, which involves the use of molecule-embedded metal@silica core-shell nanoparticles as information carriers. A shadow-mask-lithography-assisted self-assembly is developed for the fabrication of the plasmonic security labels. The produced security labels show multiple sets of coding information that are highly unique, technically unreplicable, and can be robustly decoded by portable microscopes within seconds.