The NSA has since sought to dismiss that remark as a quip taken out of context. In his new book, "No Place to Hide," Glenn Greenwald, one of three recipients of the voluminous, top-secret material that NSA contractor Edward Snowden chose to leak, uses those documents to prove that this was indeed the agencys guiding principle.

In one remarkable slide presented at a 2011 meeting of five nations intelligence agencies and revealed here for the first time, the NSA described its "collection posture" as "Collect it All," "Process it All," "Exploit it All," "Partner it All," "Sniff it All" and, ultimately, "Know it All."