Quantum computing will make online heists likelier than we can fathom

livemint.com:

how to break down small integers like 15 and 21, these were the first demonstrations of ‘Shor’s algorithm,’ a method of quantum factorization that does not get exponentially more time-consuming as the number gets bigger. In August, Oded Regev of New York University proposed what many consider the first big improvement to Peter Shor’s 1994 technique. If it works, the time taken to decode complex ciphers may shorten.

By 2030, a $1 billion quantum computer may be able to break RSA Laboratories’ widely used 2048-bit encryption by factoring a 617-digit number in a few hours, according to a 2016 estimate by the National Institute of Standards and Technology in Maryland. NIST has come up with new protocols that will be resistant to quantum computers, but what if the threat arrives before the weaponry to ward it off has been adopted? Retail losses may be kept to manageable levels, at least for a while. But a wholesale quantum heist would be catastrophic.

The security of worldwide interbank payments may be compromised if the digital signatures authorizing release of funds lose their sanctity. Scammers already have a blueprint in the $81 million theft from Bangladesh’s accounts with the Federal Reserve Bank of New York in 2016. It isn’t just the security of existing products that’s at stake; innovative new payment instruments will be affected, too.

Monetary authorities are experimenting with paperless cash. The Bank for International Settlements estimates that by 2030, there may be 15 central bank digital currencies (CBDCs) in retail circulation. Tourbillon, a recent BIS project, has shown that the cash-like privacy that users will expect of these instruments may be realizable.