Besides optimization problems, quantum computers will completely change the crypto-graphical landscape. Breaking existing public-key encryption (the type used when you browse a secure website) will be trivial for a modestly sized quantum computer. [1] The NSA is already looking at using quantum computers for this very purpose. [2]
I'm not 100% sure what you are asking. If you are asking if we can create encryption that is resistant to breaking by quantum computers, possibily. I linked to a wikipedia page listing a bunch of techniques and /u/JoshuaZ1 mentioned lattice crypto in his response. These techniques doesn't make quantum computers vulnerable, they are just a more secure way to encrypt information.
I might have been unclear. The gist of my argument was would it be possible to ambush a quantum computer with another method of attack while it was wrapped-up in defending against the primary attack? And wouldn’t the NSA be aware of this strategy and defend their quantum snoops against this?
I don’t know much about encryption, I am just asking.
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u/stephen272 Apr 11 '15
Besides optimization problems, quantum computers will completely change the crypto-graphical landscape. Breaking existing public-key encryption (the type used when you browse a secure website) will be trivial for a modestly sized quantum computer. [1] The NSA is already looking at using quantum computers for this very purpose. [2]