While some argue that the fact that ISIS is using encryption is a good reason to break encryption — it is a little like saying that because ISIS uses guns, then the West should ban guns too (hm, might not be a bad argument after all…) — the fact is that banning their channels from existing communication services will not be enough as they will certainly setup new channels. In any case it is a measure that can have some effect on the recruitment and propaganda. If we make ISIS propaganda expensive (both in terms of cost and in terms of man-hours to setup, a bit like making SPAM expensive by forcing them to buy more servers), and with limited reach, then we might start winning part of this war. On the other hand it might also create the illusion that they are under control. Don’t get into that delusion. Telegram shutting down ISIS sites and all the active monitoring and control of ISIS propaganda is just a small step. Their activities need to be stopped on a global level.