GEORGE DYSON, Science Historian, is the author of Turing's Cathedral: The Origins of the Digital Universe, and Darwin Among the Machines.
The Corona program, a joint venture between the CIA, the NSA, and the Department of Defense, was coordinated by the Advanced Research Projects Agency (ARPA) and continued, under absolute secrecy, for 12 more years and 126 more missions, becoming the most productive intelligence operation of the Cold War. "It was as if an enormous floodlight had been turned on in a darkened warehouse," observed former CIA program director Albert D. Wheelon, after the operation was declassified by order of President Clinton in 1995. "The Corona data quickly assumed the decisive role that the Enigma intercepts had played in World War II."
The resources and expertise that were gathered to support the Corona program, operating under cover of a number of companies and institutions centered around Sunnyvale, California (including Fairchild, Lockheed, and the Stanford Industrial Park) helped produce the Silicon Valley of today. Google Earth is Corona's direct descendant, and it is a fact as remarkable as the fall of the Berlin wall that anyone, anywhere in the world, can freely access satellite imagery whose very existence was a closely guarded secret only a generation ago.
PRISM, on the contrary, has been kept in the dark. Setting aside the question of whether wholesale, indiscriminate data collection is legal—which, evidently, its proponents believed it was—the presumed reason is that for a surveillance system to be effective against bad actors, the bad actors have to be unaware that they are being watched. Unfortunately, the bad actors to be most worried about are the ones who suspect that they are being watched. The tradecraft goes way back. With the privacy of houses came eavesdropping; with the advent of written communication came secret opening of mail; with the advent of the electric telegraph came secret wiretaps; with the advent of photography came spy cameras; with the advent of orbital rocketry came spy satellites. To effectively spy on the entire Internet you need your own secret Internet—and Edward Snowden has now given us a glimpse into how this was done.
The ultimate goal of signals intelligence and analysis is to learn not only what is being said, and what is being done, but what is being thought. With the proliferation of search engines that directly track the links between individual human minds and the words, images, and ideas that both characterize and increasingly constitute their thoughts, this goal appears within reach at last. "But, how can the machine know what I think?" you ask. It does not need to know what you think—no more than one person ever really knows what another person thinks. A reasonable guess at what you are thinking is good enough.
Data mining, on the scale now practiced by Google and the NSA, is the realization of what Alan Turing was getting at, in 1939, when he wondered "how far it is possible to eliminate intuition, and leave only ingenuity," in postulating what he termed an "Oracle Machine." He had already convinced himself of the possibility of what we now call artificial intelligence (in his more precise terms, mechanical intelligence) and was curious as to whether intuition could be similarly reduced to a mechanical procedure—although it might (indeed should) involve non-deterministic steps. He assumed, for sake of argument, that "we do not mind how much ingenuity is required, and therefore assume it to be available in unlimited supply."