Spy Dust
Used by the Soviet Union during the Cold War:
A defecting agent revealed that powder containing both luminol and a substance called nitrophenyl pentadien (NPPD) had been applied to doorknobs, the floor mats of cars, and other surfaces that Americans living in Moscow had touched. They would then track or smear the substance over every surface they subsequently touched.
Andrew Wallace • May 20, 2015 8:51 AM
I don’t think the Cold War ever ended and the Cyber Cold War has just begun. 🙂
Andrew