Among the smart, café-going crowd in Bangladesh, the Holey Artisan Bakery is an established favorite. Bright and airy, the eatery in downtown Dhaka had a dedicated following among locals and expats alike. That was before the evening last summer, when the restaurant earned a new and terrible reputation. As diners gathered to break their Ramadan fast, Islamic militants attacked the building, seizing guests and staff as hostages. At the end of a 12-hour siege, 29 people were dead, including five terrorists.
But the death toll was only part of the horror. In a macabre gesture, the militants sent out pictures of their victims, some slashed with machetes. Their chosen medium? Threema, a secure messaging app based in Switzerland, that investigators believe terrorists may also have used to plan their attack. To the dismay of security services across the region, tech-savvy militants are turning to encryption services offered by many European companies, including in Germany, to coordinate their activities and spread their propaganda.
If easy access to encryption is bad news for local intelligence agencies, it could also emerge as a source of international tension. On the one hand, remembering the widespread alarm after U.S. whistleblower Edward Snowden revealed the extent of U.S. electronic surveillance, privacy-sensitive Europeans and Americans welcome the guaranteed security offered by fast-developing encryption technologies. On the other, intelligence chiefs fighting on the front line of the war on terrorism see encryption as one more obstacle to monitoring or tracking down militants. As terrorists know all too well, encryption can effectively encode any data beyond recognition. ISIS is said to recommend Threema to its activists.