Sycamore Quantum Computer chip from Google
A sufficiently powerful quantum computer could break the encryption methods currently used to protect data worldwide. But the solution may be a quantum algorithm once considered completely useless.
One “useless” algorithm which serves as a reference to demonstrate the power of quantum computers on common devices could potentially be reused as a way of maintaining safe data – against, ironically, quantum computers.
Quantum computers have long threatened to break the existing encryption algorithms, which depend on Difficult problems to solve For classic computers, such as finding the cousin factors of a large number. A sufficiently powerful quantum computer could do so.
But Bill Feffermanfrom the University of Chicago, and his colleagues, say that the same type of device could also offer a solution.
According to the idea, it is based on the determination of the result of a random quantum circuit executed on a quantic computerthe. Such a result is Easy to check if we know what the circuit is likebut find out the form of the circuit only from the result It’s very difficult.
This algorithm of Random circuit sampling (RCS) It is already used as a kind of reference for quantum computers, to identify the point where they reach the call – when a quantum computer becomes able to do something that No classic computer can.
How it was thought that this algorithm I had no purpose particularly useful, such efforts have been criticized as meaninglessso finding an application in the encryption would be very useful.
There is only one problem: Quantum supremacy allegations are often refuted when it is discovered that classic computers can solve the RCs – which means the given problem may not be “Difficult” sufficiently to be used in cryptografia.
Came from Google in 2019, when the company stated that its Sycamore Quantum Computer could perform calculations that would even lead to the world’s most powerful classic supercomputer 10,000 years to complete. This was quickly refuted twice by different groups working on classic machines.
Fefferman says there is still no certainty about whether RCS is a problem genuinely difficultbut this is also true for current encryption methods.
Cryptography builds confidence over timeshowing that despite the great incentives – Being able to divert secrets and money on a large scale “No one still found a way to break the encryption schemes, says the investigator.”
“Anticipation that there is some debate in the community about new quantum algorithms that can learn some class of quantum circuits, ”says Fefferman.“ These classes would then be excluded from the possible circuits Chosen by the algorithm, he explains.
“As soon as we have some set that is difficult to learnWe can use it for encryption, ”concludes the researcher.
