Researchers in Russia say they've developed and tested the world's first blockchain that won't be vulnerable to encryption-breaking attacks from future quantum computers.
If the claims are verified, the technique could be a means of protecting the vast amounts of wealth invested in fast-growing cryptocurrencies like Bitcoin and Ethereum – which are safe from today's code-breaking methods, but could be exposed by tomorrow's vastly more powerful quantum machines.
A team from the Russian Quantum Centre in Moscow says its quantum blockchain technology has been successfully tested with one of Russia's largest banks, Gazprombank, and could be used as a proof of concept to underpin secure data encryption and storage methods in the future.
To backtrack a little, a blockchain is a publicly accessible, decentralised ledger of recorded information, spread across multiple computers on the internet.
This kind of distributed database is the underlying technology that makes Bitcoin possible – where it maintains a list of timestamped digital transactions that can be viewed by anyone on the platform.
The idea is that the blockchain frees users on the network from needing any kind of middleman or central authority to regulate transactions or exchanges of information.
Because all interactions are recorded in the distributed ledger, the blockchain makes everything a matter of public record, which, when it comes to Bitcoin, is what ensures that transactions are legitimate, and that units of the currency aren't duplicated.
The problem with this is that when someone's computer conducts transactions, the system uses digital signatures for authentication purposes – but while that protection layer may offer strong enough encryption to secure those exchanges today, they won't be able to withstand quantum computers.
While that means quantum computers are poised to do great things for us in tomorrow's world, it's a double-edged sword – because that massive increase in performance also means these machines could pose a huge security risk in the world of IT, breaking through comparatively weak encryption walls that currently protect the world of banking, defence, email, social media, you name it.
"If quantum computing takes three decades to truly arrive, there's no reason to panic," as Nicole Kobie reported for Wired last year.
"If it lands in 10 years, our data is in serious trouble. But it's impossible to predict with certainty when it will happen."
Because of this, today's security researchers are busy trying to invent secure systems that can defend us from the unbelievably fast supercomputers of tomorrow – a pretty tall order, considering these awesome systems haven't even really been invented yet.
That's what the Russian team's quantum-proof blockchain is – another attempt to devise a digital fortress that won't be crushed by quantum computers. And the key, the researchers say, is abandoning part of what currently helps protect blockchain transactions.
"In our quantum-secure blockchain setup, we get rid of digital signatures altogether," one of the researchers, Alexander Lvovsky, told Mary-Ann Russon at IBTimes UK.
"Instead, we utilise quantum cryptography for authentication."
Quantum cryptography depends on entangled particles to work, and the researchers' system used what's called quantum key distribution, which the researchers say makes it possible to make sure nobody's eavesdropping on private communications.
"Parties that communicate via a quantum channel can be completely sure that they are talking to each other, not anybody else. This is the main idea," Lvovsky said.
"Then we had to re-invent the entire blockchain architecture to 'fit' our new authentication technology, thereby making this architecture immune to quantum computer attacks."
The system they've experimented with was tested on a 3-node (computer) network, but it's worth pointing out that while the team is claiming victory so far, this kind of research remains hypothetical at this point, and the study has yet to undergo peer-review.
But given the looming technological avalanche that quantum computers represent for digital security, all we'll say is we're glad scientists are working on this while there's still time.
Because, make no doubt, the future is headed this way fast.
The study has been published on pre-print website arXiv.org.