Quantum computers that can perform vast numbers of calculations simultaneously may be closer to science fiction than reality, but previously unpublished documents indicate the secretive U.S. National Security Agency is working hard to build a real quantum supercomputer, powerful enough to decode virtually every form of encryption now known.
Such a computer, many times faster than today’s fastest machines, could easily solve codes now considered "unbreakable" - the type of ciphers currently used worldwide by scientific and financial institutions and governments to protect their data.
The basic principle of quantum computing is a physical phenomenon that is not yet fully understood: certain subatomic particles can simultaneously exist in two different states. A conventional computer works with binary "bits" of information that are represented as either zero or one; quantum bits could be both zero and one simultaneously.
In theory, that quirk of physics will allow quantum computers to skip through much of the elaborate mathematical computations necessary to solve complex encryption keys.
Documents made public by former NSA contractor Edward Snowden show the code-breaking agency is spending nearly $80 million on a secret research program called "Penetrating Hard Targets."
NSA would not comment on this week's disclosures by Snowden, who has been living in asylum in Russia since last year, after exposing secret U.S. diplomatic cables and worldwide surveillance activities.
The U.S. government is said to be competing against quantum-computer research efforts by the European Union and Switzerlands, but experts in the field say practical exploitation of such systems is years if not decades in the future.