Nanoparticles are incorporated into bulletproof vests which gives them a better resistance [J-H. Lee et al., Nature communication 3 (2012) 1164].
"Security" applications concern protection against shocks (bumper, bullet proof jacket) or fire (clothing with nanoclay) as well as against counterfeiting (tracing) or robbery (RFID). At the Defense level, known applications are: detectors and correctors of chemical and biological agents, miniaturized monitoring systems, and more precise guidance systems.