His answer was to begin “tracking everyone, all the time”, said an officer who worked for Sariel at the time. Instead of traditional surveillance of specific targets, Sariel’s project relied on mass surveillance of Palestinians in the West Bank and used novel AI methods to extract insights. “Suddenly the entire public was our enemy,” said another source who worked on the project, which sought to predict whether someone represented a threat to Israeli security. One system developed in this period, sources said, scanned all text messages between Palestinians in the West Bank and assigned each message a risk rating based on an automated analysis of whether it included words deemed to be suspicious. Still in use, the system – known as “noisy message” – can identify text messages in which people talk about weapons or discuss wanting to die.