Just how much access does the NSA have to all unencrypted communications?

In case you haven't been following the news, the encryption wars are back and a huge Apple vs. FBI clash is the latest major conflict. The FBI wants access to the iPhone that belonged to one of the shooters in the San Bernardino massacre, and Apple is refusing to offer it. But long before this week's big battle, there was a debate over the role that encryption played in the deadly terrorist attacks in Paris last November. The NSA now says that the Paris attacks "would not have happened," without...