In a technology lab full of graduate students huddled over laptops, Prof. Marios Savvides flipped through photos on a computer screen searching for one full of people whose faces were barely recognizable to the human eye.

“How about a riot?” Professor Savvides asked. He had just come upon an image of police officers wearing helmets and gas masks and rioters covering their mouths and noses with bandannas — all trying to shield themselves from the tear-gas- and smoke-filled air.
https://www.nytimes.com/2018/11/14/business/learning-to-attack-the-cyber-attackers-cant-happen-fast-enough.html