Blockchain technology has taken the world by storm in recent years as a way to anonymously record transactions between individuals. As safe is it is currently, it’s only a matter of time before somebody finds a way to tap into those coded messages.
While quantum computing potentially opens the way to some serious safe-cracking power for hackers, the delicate nature of entanglement might also provide the solution to keeping data secure – by reaching into the past and erasing its own history.
A pair of researchers from Victoria University of Wellington in New Zealand have developed their own concept for a quantum blockchain that would theoretically prevent anybody from unknowingly fiddling with your electronic ledgers.
Blockchain technology is best known for its role in systems of economics known as cryptocurrency.
Where your traditional pounds and dollars are tied to a state-owned banking system, methods of payment such as ‘Bitcoin‘ depend on a decentralised network of encrypted transactions.
This publically available ‘bank-book’ has the advantage of doing away with any kind of human authority by using a set of algorithms to time-stamp and evaluate each currency-based exchange across a series of computers on the internet.
This distributed form of decision making makes blockchain technology perfectly suitable for virtually any democratic process, from a publically owned banking system to building companies that don’t have a CEO.
But this system is reliant on a relative transparency to the general public, something that also makes it vulnerable to exploitation.
Right now, transactions are locked up with heavy levels of encryption that even the fastest supercomputers would have a hard time cracking in a reasonable amount of time.
The problem is that quantum computing just might change all of that.
By making use of algorithms based on the fuzzy guessing-game of undecided quantum states, computers could soon be crunching through traditional forms of encryption in no time.
Luckily the same phenomenon behind this tech offers a neat new angle on how to secure a message.
The quantum properties of a particle technically don’t exist in a defined state until we measure them in some way. It’s like having a glove in a box – until you look, it’s neither left-handed nor right-handed.
Stranger still, if that particle was associated with another particle at some point in time – like a pair of gloves pulled from the same packet – observing one instantly tells you the state of its partner, no matter how far apart the two objects happen to be.
Once ‘seen’, the particle settles on a state and tells its partner to take a complimentary form, spilling the beans on any compromised transmission.
Referred to as entanglement, this is currently being used to add signatures to communications that will alert users to whether an outsider has tapped in to listen.
This also isn’t the first time it’s been applied to blockchains. Last year researchers from the Russian Quantum Centre created and tested a way to replace traditional encryption with a quantum form.
But there’s more than one way to skin Schrodinger’s cat, and the entanglement process doesn’t just work over spatial distances.
“Perhaps more shockingly, our encoding procedure can be interpreted as non-classically influencing the past,” the researchers write.
“Hence this decentralised quantum blockchain can be viewed as a quantum networked time machine.”
This quantum time-stamping is what makes it so powerful for building the blockchains themselves, and not just wrapping their bits in an encrypted sleeve.
Interfering with current records in a quantum blockchain’s digital ledgers in any way would affect the record of their own history, altering entries recorded in the past which invalidates related records in a digital lock-down procedure.
The proposal is available on the pre-review website arxiv.org for anybody to view, and also hasn’t been put to the test just yet.
Still, it’s a clever new way to make use of quantum weirdness, ensuring blockchain technology will stay secure well into the future.