IBM unveils a 433-qubit quantum computer

IBM has today unveiled a 433-qubit quantum processor – progress in the field is accelerating.

One of the example uses of quantum computers is prime factorisation, which they can do much faster than can classical computers. One reason this is of interest is that the security of public key encryption – used everywhere on the net, from LinkedIn to banks – depends on the computational difficulty of prime factorisation.

To break a 2048-bit RSA public key would take trillions of years on a classical computer. A paper published last year argued that a 2048-bit RSA public key could be cracked in 8 hours on a quantum computer. However, that would require 20,000,000 qubits – rather more than the 433 announced today. So, our secrets seem to be safe for a while yet.