That's the buzz phrase, “go dark”. This means that, if you are an investigator, all of a sudden all of your access to information evaporates, because not only the material but the systems that carry the material are so heavily encrypted you are not able to even detect the trail that you might like to follow. That is a huge issue that is technological on one side, and legal and constitutional on the other side. It would be very useful to hear the debate in the committee and the evidence of the witnesses you might call, to delve more deeply into that very critical field. It's a field that had a bearing on the ability to detect, or not, the activities of Mr. Driver.
On October 6th, 2016. See this statement in context.