By Hamish Johnston
An article in the Washington Post claims that the US National Security Agency (NSA) is funding research into how quantum computers could be used to crack cryptography systems. While the article claims to be based on leaked secret documents, the revelation doesn’t seem to surprise several of the physicists quoted in the piece.
Scott Aaronson of the Massachusetts Institute of Technology (MIT) says that it’s unlikely that the NSA project is much further ahead of public quantum-computing research. His MIT colleague Seth Lloyd adds that it could be five years or more before the NSA or anyone else creates a quantum computer capable of breaking cryptographic systems.
Interestingly, Lloyd alludes to a space-race-like rivalry between the US, EU and Switzerland that is driving the development of code-busting quantum computers.
Conventional cryptography systems are used to protect vast amounts of financial, medical and other information that is exchanged over the Internet. Cracking these systems involves the brute-force factoring of very large numbers. While standard computers can take an eternity to do this, quantum computers should be able to complete the task in a reasonable amount of time.
But don’t think that quantum systems are all bad news for the keepers of secrets. There is one type of cryptography that cannot be cracked by any quantum computer: quantum cryptography.
Commercial quantum-cryptography systems already exist and as the technology improves it could provide the perfect foil to snoopers using quantum computers. There are, however, other ways of cracking quantum-cryptography systems and I’m sure the NSA and other spy agencies are busy developing these as well.
The Washington Post article is: “NSA seeks to build quantum computer that could crack most types of encryption“.
You can learn more about quantum computers in this podcast that I recorded with some of the leading lights in quantum computing: “Quantum computing: challenges, triumphs and applications“.
There is much more about the first commercial quantum cryptography systems in the article “Key to the quantum industry” and last year I met a (very public) quantum hacker when visiting the University of Waterloo.