There was much excitement in japan this summer when fujitsus $1bn fugaku supercomputer was officially declared the worlds fastest, ableto perform a staggering 416 quadrillion calculations per second.
But there are some mathematical problems that even a classical computer as mighty as fugaku cannot crack, which is a good thing for the security of our online credit card transactions.
Standard rsa encryption works on the basis that it is very easy for a classical computer to multiply two prime numbers, but practically impossible to find the factors of that number provided it is sufficiently big. however, in 1994 the mathematician peter shor invented an algorithm that could run on a quantum computer to solve that factoring problem. the only trouble with shors algorithm is that no one has yet invented a sufficiently stable quantum computer on which it could work.
We are now entering a world where this might one day be possible, with mind-bending implications for the security of billions of connected devices. thankfully, though, we are even closer to devising more secure methods of encryption.
Last week, cambridge quantum computing announced the first commercial, verifiable quantum random generation number service designed to run on an existing ibm quantum computer. initially, the service will only be available to the 100 or so corporate and academic members of ibms q network but it will be open to other users later this year. its first applications are likely to be for cryptography, material science, computer games, insurance and options pricing.
Ilyas khan, chief executive of the uk start-up, says that what makes cqcs service different from other existing random generation systems is that it is certifiably quantum, maximally random, accessible on the cloud, and deliverable on any quantum computer. it can also be used to power quantum key distribution, a secure method of communication.
There is no algorithm involved. there is no determinism involved. there are no patterns that can be cracked, he says. people consume randomness. they pay for this. it is an essential fuel oil for computational tasks all over the world.
Progress in the fiendishly complex field of quantum computing has been frustratingly elusive, as technologists have struggled to build computers with reliable enough qubits, or quantum bits, to do much useful. manipulating subatomic particles is extremely tricky given that any disturbance can cause qubits to become unstable.
But things have been picking up fast over the past couple of years with some striking advances in both hardware and software. governments, private companies and venture capitalists have all been increasing investments in the sector, even if they have no idea when they might generate a return.
Last week, ibm declared its ambitions to create a full-stack quantum computer accessible on the cloud by anyone around the world. it said it would unveil a 127-qubit computer next year, and would surpass 1,000 qubits in 2023.
Roger mckinlay, challenge director for quantum technologies at uk research and innovation, says that for a long time quantum computer scientists have overwhelmingly focused on the technology but are now increasingly turning their minds to commercial applications.
The number of qubits you need to do something useful is going down while the number of qubits is going up. when we get to a 100-qubit machine and some real software then some interesting things will happen, he says.
For decades, quantum computing has been hailed as a miracle technology that reliably fails to materialise. it reminds some of the old joke about brazil: quantum computing is the technology of the future and always will be.
We are still many years, if not decades, away from the widespread use of quantum computing. further setbacks are inevitable. but it is finally time for mainstream companies to start paying close attention.