Should Shor's Algorithm Scare Me? by James Birnie

Quantum computers are going to break RSA. Is this true? If so, when will it happen? How worried should I be? If quantum computers do become powerful enough to break RSA it will be because of Shor's algorithm for factorising numbers. Shor's algorithm is in complexity class BQP. This means that it works in polynomial time with respect to the size of the number to be factorised. For all practical purposes, this means that the only thing keeping RSA secure is the non existence (or at least non known existence) of quantum computers powerful enough to factorise any number larger than 15. I'll explain how Shor's algorithm works, why it is important and what we can do to prevent having all our secrets exposed when the computers exist to break all the encryption we are currently using.