Tagging People with Invisible Ink
In Montreal, police marked protesters with invisible ink to be able to identify them later. The next step is going to be a spray that marks people surreptitiously, maybe with SmartWater.
EDITED TO ADD (12/14): Official explanation.
Posted on December 7, 2011 at 6:13 AM •
Sidebar photo of Bruce Schneier by Joe MacInnis.