ISIS videos became such a staple on YouTube that the site’s automated advertising algorithms were inserting advertisements for Procter & Gamble, Toyota and Anheuser–Busch in front of videos associated with the terrorist group. Whether Google had turned a blind eye to such content is a matter of debate, primarily between the company and the Counter Extremism Project (CEP). Dr. Hany Farid, a Dartmouth College computer science professor who helped Microsoft develop PhotoDNA nearly a decade ago to crack down on online child pornography, has been working with CEP for more than a year to develop eGLYPH, which analyzes video, image and audio files, and creates a unique signature—called a “hash”—that can be used to identify either an entire video or specific scenes within a video. CEP has built up a vast repository of hashed images, audio files and video that “contains the worst of the worst—content that few people would disagree represented acts of terrorism, extremist propaganda and recruiting materials,” says Mark Wallace, CEP’s chief executive officer and a former U.S. ambassador. The CEP has offered free access to both eGLYPH and the organization’s database to social media outlets trying to keep up with terrorism-related video posts.