Post-Quantum Cryptography Scheme Is Cracked?

 Generally true? Is this easily fixable, say by adding more digits? This kind of work, which challenges new methods is key. 

‘Post-Quantum’ Cryptography Scheme Is Cracked on a Laptop

Two researchers have broken an encryption protocol that many saw as a promising defense against the power of quantum computing.

By Jordana Cepelewicz, Senior Writer,    QuantaMagazine

If today’s cryptography protocols were to fail, it would be impossible to secure online connections — to send confidential messages, make secure financial transactions, or authenticate data. Anyone could access anything; anyone could pretend to be anyone. The digital economy would collapse.

When (or if) a fully functional quantum computer becomes available, that’s precisely what could happen. As a result, in 2017 the U.S. government’s National Institute of Standards and Technology (NIST) launched an international competition to find the best ways to achieve “post-quantum” cryptography.

Last month, the agency selected its first group of winners: four protocols that, with some revision, will be deployed as a quantum shield. It also announced four additional candidates still under consideration.

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Then on July 30, a pair of researchers revealed that they had broken one of those candidates in an hour on a laptop. (Since then, others have made the attack even faster, breaking the protocol in a matter of minutes.) “An attack that’s so dramatic and powerful … was quite a shock,” said Steven Galbraith, a mathematician and computer scientist at the University of Auckland in New Zealand. Not only was the mathematics underlying the attack surprising, but it reduced the (much-needed) diversity of post-quantum cryptography — eliminating an encryption protocol that worked very differently from the vast majority of schemes in the NIST competition.

“It’s a bit of a bummer,” said Christopher Peikert, a cryptographer at the University of Michigan.

The results have left the post-quantum cryptography community both shaken and encouraged. Shaken, because this attack (and another from a previous round of the competition) suddenly turned what looked like a digital steel door into wet newspaper. “It came out of the blue,” said Dustin Moody, one of the mathematicians leading the NIST standardization effort. But if a cryptographic scheme is going to get broken, it’s best if it happens well before it’s being used in the wild. “There’s many emotions that go through you,” said David Jao, a mathematician at the University of Waterloo in Canada who, along with IBM researcher Luca De Feo, proposed the protocol in 2011. Certainly surprise and disappointment are among them. “But also,” Jao added, “at least it got broken now.”  .... '