Quantum Computing Not an Imminent Threat To Public Encryption 119
Bruce Schneier's latest blog entry points out an interesting analysis of how quantum computing will affect public encryption. The author takes a look at some of the mathematics involved with using a quantum computer to run a factoring algorithm, and makes some reasonable assumptions about the technological constraints faced by the developers of the technology. He concludes that while quantum computing could be a threat to modern encryption, it is not the dire emergency some researchers suggest.
not exactly a "threat" (Score:4, Insightful)
The day PKIs that use factoring or discrete logs become easy to crack is the day when there's going to be a lot of tremendous amount of money spent on stop-gap security measures until someone figures out something new...
the fear (Score:2, Insightful)
Re:not exactly a "threat" (Score:4, Insightful)
I imagine one-time pads will come back in style.
Comment removed (Score:3, Insightful)
Re:Schneier knows his stuff (Score:3, Insightful)
Re:not exactly a "threat" (Score:3, Insightful)
Well, just think about all the SSL enabled sites out there, and remember you will now have a N * N (client * server) number of relations that need to setup a symmetric key (which is what a one time pad is, basically). Also note that you don't have a certificate infrastructure, so you cannot just go to VeriSign or any other trusted third party and buy a certificate from there. You cannot download one time pads, because you don't know who it is coming from.
Say you have 200.000.000 client computers in the US alone, and some 5.000 sites with one time pad SSL. Then you have 1.000.000.000.000 relations to set up. Not quite as much as the number of dollars wasted on the war in Iraq, but it's getting there. Of course, you won't use each and every service, but it would take a little bit too much time to exchange disks by post when you are trying to connect to a new service.
Re:Schneier knows his stuff (Score:5, Insightful)
The darned things would be like oracles, just ask them any super hard question, like how to prove Fermat's Last Theorem, and they'd just spit out the answer. The things would be like talking directly to God. Is that even remotely possible? I don't think so. Factoring numbers is just not as hard as any NP complete problem.
You might as well conclude that grass is purple, for all the sense that paragraph makes.
You have to get the pads to the other person... (Score:3, Insightful)
If you have a way of transmitting the pads securely then you could just use the same system to transmit the messages - no encryption needed!