What Quantum Computing Means for National Security

If cyberwarfare is the Cold War of the new millennium, quantum computation may be the hydrogen bomb.

Researchers with Google, D-Wave (a Canadian computer hardware company), and the U.S. government are looking to quantum physics to make vastly more-capable computers. They may also find the key to making certain networks, pages, or computers nearly invincible to cyberattacks, or render certain Internet security systems completely defenseless.

Quantum computation harnesses the unique behavior of subatomic particles — behaviors that don’t occur anywhere else in nature above this incredibly small scale. Scientists view quantum physics as distinct from regular physics for this reason. It’s also why subatomic particles can be made to compute information differently than their bulkier macro-scale counterparts.

Regular computers function through the use of transistors. An electric current running through the transistor activates a switch, turning the switch either on or off, thus giving it a value of either one or zero. Lots of activated switches create the binary computer codes of ones and zeros that compose all computer functioning. But quantum bits of information (qubits) can convey a value of one, zero, or both at once because certain subatomic particles can exist in more than one state (known as a superposition). If scientists can direct the powers of these in-between numbers, they can use them to solve mathematical problems, called quantum algorithms, which have long eluded solutions.

A quantum computing breakthrough could, in turn, enable governments to break otherwise impervious encryption codes such as the “public key” cryptographic systems that protect your e-mail and bank account. Cracking the public key could render such security measures worthless. The same trick could be reversed to create essentially unbreakable encryption codes.

One potentially vulnerable code is the public key system based on a supremely difficult math problem called Shor’s algorithm. Cryptography may sound like some obscure security concept of little relevance to civilians, but millions of people interact with public key codes every day.

For instance, thousands of U.S. banks rely on a type of public key system called RSA (named for Ron Rivest, Adi Shamir, and Leonard Adleman, its inventors) to provide users with private online account access. Web sites around the world use a public key system called the Digital Signature Algorithm (DSA) when they integrate Google code into their sites’ functioning, in order to keep areas of their site visible only to secure, approved users. Home WiFi networks employ various “public keys” to keep their networks closed to hackers (or neighbors who refuse to buy their own routers). As more sensitive data — possibly involving medical records or the electric grid — is brought online, the use of simple encryptions like RSA and DSA will likely increase, potentially spreading vulnerabilities across the system

“There is a national security interest in not being the second country to build a large quantum computer,” says Dave Bacon, a computer scientist at Washington University.

Recently, scientists at the National Institute of Standards and Technology (NIST) unveiled what they called “the world’s most efficient single photon detector,” which is purportedly able to count individual particles of light traveling through fiberoptic cables with roughly 99% efficiency. The announcement could have ramifications for quantum computing efforts and for secure networking. A detector that could recognize if a photon forming part of a transmission were missing would be a substantial defense against information theft, say researchers.

According to the Intelligence Advanced Research Projects Activity (IARPA), several research groups have built functioning multiple qubit processing systems in which two qubits were able to interact in a stable way.

Canadian company D-Wave is the industry pioneer in the building of these processors, having invested $44 million over the last five years. The biggest chips the company has feature 128 total qubits, according to D-Wave chief technical officer Geordie Rose. (Not all of qubits interact — or form an “entanglement gate” — on the chip, however.) Last December, the Google image recognition team led by Hartmut Neven demonstrated a search algorithm that could differentiate objects in thousands of still photographs. The demonstration was run on the D-Wave chip developed by Rose.

A number of technological hurdles remain before these chips can show their superiority to regular processors. Researchers will have to maintain and improve control over the chips’ quantum operations in more complex environments. Additional challenges will arise from trying to increase the density of the qubits used in the devices.

Rose says the net knowledge gain from quantum computing R&D is probably wider than we can imagine. “A universal quantum computer is the most powerful computer possible in our universe,” he told THE FUTURIST. “Anything better would quite literally violate the laws of physics.” — Patrick Tucker

Sources: Intelligence Advanced Research Projects Activity. www.iarpa.gov.

D-Wave, personal interviews with Dave Bacon, Geordie Rose. A detailed paper on the D-Wave processor may be obtained at: http://arxiv.org/abs/1004.1628.

Further reading: “Recent Progress in Quantum Algorithms” by Dave Bacom and Wim van Dam, Communications of the ACM.