LWN.net needs you! Without subscribers, LWN would simply not exist. Please consider signing up for a subscription and helping to keep LWN publishing. Shor's algorithm is the main practical example of an algorithm that runs more quickly on a quantum computer than a classical computer — at least in theory. Shor's algorithm allows large numbers to be factored into their component prime factors quickly. In reality, existing quantum computers do not have nearly enough memory to factor interesting nu...