NSA seeks to build quantum computer that could crack most types of encryption
By Steven Rich and Barton Gellman, Published: January 2, 2014

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.
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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 NSA’s code-breaking mission. With such technology, all forms of public key encryption would be broken, including those used on many secure Web sites as well as the type used to protect state secrets.

Physicists and computer scientists have long speculated whether the NSA’s efforts are more advanced than those of the best civilian labs. Although the full extent of the agency’s research remains unknown, the documents provided by Snowden suggest that the NSA is no closer to success than others in the scientific community.
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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 don’t 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.

A working quantum computer would open the door to easily breaking the strongest encryption tools in use today, including a standard known as RSA, named for the initials of its creators. RSA scrambles communications, making them unreadable to anyone but the intended recipient, without requiring the use of a shared password. It is commonly used in Web browsers to secure financial transactions and in encrypted e-mails. RSA is used because of the difficulty of factoring the product of two large prime numbers. Breaking the encryption involves finding those two numbers. This cannot be done in a reasonable amount of time on a classical computer.
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