This article is good:
http://www.washingtonpost.com/blogs/...t-can-explain/
"Almost all of the public-key encryption that is currently used would be breakable in principle by a quantum computer. That includes RSA, Diffie-Hellman, ElGamal, elliptic curve cryptography. On the other side, if you look at private-key cryptography, the kind where you have to agree on the key in advance, then most private-key cryptography you don't know how to break with a quantum computer."
"Another response that you could take, ironically, is to switch to quantum cryptography. It's a completely different way of doing encryption. It uses fiber-optic cables that can transmit photons that maintain polarization. Cryptography based on quantum mechanics, the uncertainty principle. This is actually practical right now. There are companies that sell quantum crypto devices: ID Quantique and Magiq. They do work, but there is a limited market for them. It's an exotic solution to a problem that most people think is solved with existing cryptography. Some people joke that the point of quantum computers is to create a market for quantum cryptography."
http://www.idquantique.com/
http://www.idquantique.com/network-e...tribution.html
http://www.idquantique.com/network-e...ology/qkd.html
http://www.idquantique.com/network-e...-security.html
http://www.magiqtech.com/
http://www.magiqtech.com/MagiQ/Produ...sheet-2011.pdf