At the Aspen Security Forum two weeks ago, James Comey (and others) explicitly talked about the "going dark" problem, describing the specific scenario they are concerned about. Maybe others have heard the scenario before, but it was a first for me. It centers around ISIL operatives abroad and ISIL-inspired terrorists here in the US. The FBI knows who the Americans are, can get a court order to carry out surveillance on their communications, but cannot eavesdrop on the conversations, because they are encrypted. They can get the metadata, so they know who is talking to who, but they can't find...