WASHINGTON – In room-size metal boxes, secure against electromagnetic leaks, the National Security Agency is racing to build a computer that could break nearly every kind of encryption used to protect banking, medical, business and government records around the world.
According to documents provided by former NSA contractor Edward Snowden, the effort to build a cryptologically useful quantum computer – a machine exponentially faster than classical computers – is part of a $79.7 million research program titled, Penetrating Hard Targets. Much of the work is hosted under classified contracts at a laboratory in College Park, Md.
The development of a quantum computer has long been a goal of many in the scientific community, with revolutionary implications for fields like medicine as well as for the NSAs code-breaking mission. With such technology, all forms of public key encryption would be broken, including those used on many secure websites as well as the type used to protect state secrets.
Physicists and computer scientists have long speculated whether the NSAs efforts are more advanced than those of the best civilian labs. Although the full extent of the agencys research remains unknown, the documents provided by Snowden suggest that the NSA is no closer to success than others in the scientific community.
It seems improbable that the NSA could be that far ahead of the open world without anybody knowing it, said Scott Aaronson, an associate professor of electrical engineering and computer science at the Massachusetts Institute of Technology.
The NSA appears to regard itself as running neck and neck with quantum computing labs sponsored by the European Union and the Swiss government, with steady progress but little prospect of an immediate breakthrough.
The geographic scope has narrowed from a global effort to a discrete focus on the European Union and Switzerland, one NSA document states.
Seth Lloyd, professor of quantum mechanical engineering at MIT, said the NSAs focus is not misplaced. The E.U. and Switzerland have made significant advances over the last decade and have caught up to the U.S. in quantum computing technology, he said.
The NSA declined to comment for this story.
The documents, however, indicate that the agency carries out some of its research in large, shielded rooms known as Faraday cages, which are designed to prevent electromagnetic energy from coming in or out. Those, according to one brief description, are required to keep delicate quantum computing experiments running.
The basic principle underlying quantum computing is known as quantum superposition, the idea that an object simultaneously exists in all states. A classical computer uses binary bits, which are either zeroes or ones. A quantum computer uses quantum bits, or qubits, which are simultaneously zero and one.
This seeming impossibility is part of the mystery that lies at the heart of quantum theory, which even theoretical physicists say no one completely understands.
If you think you understand quantum mechanics, you dont understand quantum mechanics, said the late Nobel laureate Richard Feynman, who is widely regarded as a pioneer in quantum computing.
Heres how it works, in theory: While a classical computer, however fast, must do one calculation at a time, a quantum computer can sometimes avoid having to make calculations that are unnecessary to solving a problem. That allows it to home in on the correct answer much more quickly and efficiently.
Quantum computing is so difficult to attain because of the fragile nature of such computers. In theory, the building blocks of such a computer might include individual atoms, photons or electrons. To maintain the quantum nature of the computer, these particles would need to be carefully isolated from their external environments.
Quantum computers are extremely delicate, so if you dont protect them from their environment, then the computation will be useless, said Daniel Lidar, a professor of electrical engineering and the director of the Center for Quantum Information Science and Technology at the University of Southern California.
In 2009, computer scientists using classical methods were able to discover the primes within a 768-bit number, but it took almost two years and hundreds of computers to factor it. The scientists estimated that it would take 1,000 times longer to break a 1,024-bit encryption key, which is commonly used for online transactions.
A large-scale quantum computer, however, could theoretically break a 1,024-bit encryption much faster. Some Internet companies are moving to 2,048-bit keys, but even those are thought to be vulnerable to rapid decryption with a quantum computer.
Quantum computers have many applications for todays scientific community, including the creation of artificial intelligence. But the NSA fears the implications for national security.
The application of quantum technologies to encryption algorithms threatens to dramatically impact the US governments ability to both protect its communications and eavesdrop on the communications of foreign governments, according to an internal document provided by Snowden.
Experts are not sure how feasible a quantum computer is in the near future. A decade ago, some experts said that developing a large quantum computer was likely 10 to 100 years in the future. Five years ago, Lloyd said the goal was at least 10 years away.