After Friday’s terrorist attacks in Paris, French authorities searched for answers while ISIS claimed responsibility. In the days that have followed, France led airstrikes against ISIS targets in Syria, and Anonymous declared war on ISIS, vowing to avenge the deaths of all who were killed in the City of Light. Likewise, ISIS has promised to attack Washington D.C. if the United States helps France seek justice in any way.

How hard will it be for France and its allies to locate those responsible, particularly in the case of the alleged “mastermind” behind the attacks? Very difficult. CNN Money details a practice called “going dark,” which sounds simply terrifying. Violent extremists will “meet” in public (on social media) before taking the conversation private (through encryption):

An Islamic State jihadist schemes a plot from inside captured territory in Syria or Iraq. Using public social media networks, he finds possible partners in Europe or the Americas. Then they move into direct person-to-person chatting apps that encrypt conversations.

These methods of encryption — WhatsApp, Telegram, Facetime, and PGP — are readily available, legal, and mostly free. Authorities panic at the possibilities they’re left with when jihadists can easily communicate around the globe. What’s even more surreal is the existence of a Jihadi Help Desk. Yes, this is a thing that exists:

NBC News has learned that ISIS is using a web-savvy new tactic to expand its global operational footprint — a 24-hour Jihadi Help Desk to help its foot soldiers spread its message worldwide, recruit followers and launch more attacks on foreign soil. Counterterrorism analysts affiliated with the U.S. Army tell NBC News that the ISIS help desk, manned by a half-dozen senior operatives around the clock, was established with the express purpose of helping would-be jihadists use encryption and other secure communications in order to evade detection by law enforcement and intelligence authorities.

Aaron F. Brantly, a counterterrorism analyst at West Point, spent hundreds of hours scrutinizing the help desk’s inner workings. Brantly says the half-dozen or so staffers field inquiries from the “technically mundane to the technically savvy to elevate the entire Jihadi community to engage in global terror.” Experts fear this period following the Paris attacks will see jihadists being able to go super “dark.” With the encryption used by the help desk staff (which is scattered worldwide) in place, authorities do have reason to worry.

(Via NBC News and CNN Money)