Post Syndicated from daroc original https://lwn.net/Articles/1066156/

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 numbers using Shor’s algorithm, despite
decades of research.
A new paper provides a major step
in that direction, however. While still impractical on today’s quantum
computers, the recent discovery
cuts the amount of memory needed to attack 256-bit elliptic-curve cryptography
by a factor of 20. More interesting, however, is that the researchers chose to
publish a zero-knowledge proof demonstrating that they know a quantum circuit
that shows these improvements, rather than publishing the actual
knowledge of how to do it.