As reported on Wired.
BY ROBERT MCMILLAN
NSA Director Keith Alexander speaking at the 2009 Cyberspace Symposium. Photo DoD/Dan Rohan
The internet is abuzz over revelations that the NSA is building its own quantum computer, a machine that could crack the computer encryption codes exponentially faster than any machine available today. But this should come as no surprise.
“It’s an interesting topic,” says Scott Aaronson, a theoretical computer scientist at MIT who has followed quantum computing efforts for a good eight years. “But as far as I can see, there is no big new revelation here.”
The NSA has openly sponsored quantum computing research for close to a decade, helping to create something called the Joint Quantum Institute at the University of Maryland. And nearly five years ago, the head of the NSA, General Keith Alexander, predicted that the era of quantum computing was on the way — and that it would take the spy agency into new territory.
“I think we can see clearly out three to five years. Beyond that, things like a quantum computer start to bump up there,” Alexander told attendees at an Omaha Nebraska Cyberspace Symposium, saying that true quantum computing could be anywhere from three to 25 years away. “And when that hits, that’s a game changer. So things like that are there that we’re going to have to look at.”
The NSA documents leaked to the Washington Post by former NSA contractor Edward Snowden confirm the agency’s interest in quantum computing, though the Post reports that the agency is funding classified work at a University of Maryland laboratory called the Laboratory for Physical Sciences. We don’t know if the agency is any closer to actually completing a quantum computer than anyone else. In fact, the Postspeculates that it’s probably not.
Christopher Monroe, a University of Maryland professor and a fellow at the Joint Quantum Institute, agrees there’s “nothing very interesting” in the Posts‘s documents. “I saw this story and was amused that somebody at the Post was trying a little too hard to make a story out of nothing, probably because everybody is intrigued by this fellow Snowden,” he said in an email interview. The NSA’s involvement in quantum information science, he adds, “is well known.”
Like the Laboratory for Physical Sciences, the Joint Quantum Institute, or JQI, is a University of Maryland institution that receives NSA funding for quantum computing research, but the JQI does not do classified research.
First proposed in 1985 by a British physicist named David Deutsch, a quantum computer is a machine that operates according to the principles of quantum mechanics — the physics of very small things like electrons and photons. With a traditional computer, a transistor stores a single “bit” of information. If the transistor is “on,” it holds a “1,” and if it’s “off,” it holds a “0.” But with a quantum computer, information is held in a “qubit” that can exist in two states at the same time, thanks to the superposition principle of quantum mechanics.
That means a quantum computer can perform far more calculations at one time than any machines that obeys classical physics — something that would be incredibly useful in cracking the encryption code that protect computer data stored and sent by governments, terrorists, and large corporations. But first you have to build one.
The NSA has been simultaneously open and vague about its quantum computing intentions. Last year, it published an explainer paper on quantum computing, talking about its potential to quickly solve mathematical problems that would be impossible on today’s digital computers. But that’s pretty much what you hear from other quantum researchers. What’s interesting about the Post’s documents is the extent to which they spell out the NSA’s ambitions to use quantum computing to crack the basic infrastructure of the internet.
The NSA declined to comment for this story, but the according to a top secret Sept. 21, 2011 document, the “NSA is pursuing more than just basic, unclassified research.” It has also been secretly working on a quantum computer, which it sees as a first step toward building large scale quantum systems that could eventually “attack high-grade public key encryption systems,” the documents state.
The Post report names two NSA programs: The $80 million Penetrating Hard Targets, which includes the classified research at the Laboratory for Physical Sciences. There’s also the ominously named Owning the Net initiative, which is run out of the Laboratory for Telecommunications Sciences.
Because quantum computing promises the theoretical capacity to do math at levels that would be impossible using today’s digital computers, it’s an extremely exciting field of computer science. But it’s one that’s fraught with difficulties too.
Academics have been toying with quantum systems for a long time, but nobody is close to building the type of practical quantum computer envisioned by the NSA. Outside the agency, the furthest along is a Canadian company called D-Wave Systems. It built a machine that is now being tested by Google and NASA, but the jury is still out on exactly what type of work the D-Wave computer can actually do.
It’s also a delicate thing. Because any interference can render quantum calculations useless, it must be delicately calibrated — the computer shared by Google and NASA takes about a month to boot up — and any attempt to observe quantum calculations in process renders them useless.
According to Monroe, practical quantum computing remains in the distant future, despite the NSA’s funding. “[T]his area is still very speculative, and even optimists don’t believe that cracking codes this way will happen in the next 20 years,” he said. “That the NSA conducts and funds such research in the open tells us more than anything about how close they are.”