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First Quantum Cryptographic Data Network
jdubs writes to tell us ScienceDaily is reporting that scientists at Northwestern University and BBN Technologies have demonstrated the first truly quantum cryptographic data network. From the article: "Kumar's research team recently demonstrated a new way of encrypting data that relies on both traditional algorithms and on physical principles. This QDE method, called AlphaEta, makes use of the inherent and irreducible quantum noise in laser light to enhance the security of the system and makes eavesdropping much more difficult. Unlike most other physical encryption methods, AlphaEta maintains performance on par with traditional optical communications links and is compatible with standard fiber optical networks."
When Chuck Yeager broke the sound barrier in the Bell Aerospace X-1 rocket plane, the results were kept classified by the airforce.
I don't mean to be a pedant but this article has nothing to do with quantum computing. It just has to do with using quantum mechanics to design a data stream that is impossible to be eavedropped on according to quantum physics. See Wikipedia for more details.
The article does not explain at all what quantum cryptograpy is and how it's different from the cryptograpy we all know. Ah, but here's wikipedia to the rescue http://en.wikipedia.org/wiki/Quantum_encryption:
Quantum cryptography uses quantum mechanics for secure communications. Unlike traditional cryptography, which employs various mathematical techniques to restrict eavesdroppers from learning the contents of encrypted messages, quantum cryptography is based on the physics of information. Eavesdropping can be viewed as measurements on a physical object -- in this case the carrier of the information. Using quantum phenomena such as quantum superpositions or quantum entanglement one can design and implement a communication system which can always detect eavesdropping. This is because measurements on the quantum carrier of information disturbs it and therefore leaves traces.
assignment != equality != identity
Besides, a point-to-point quantum crypto connection was done around two years ago in Europe. Also the "article" never talks about the one thing you can't do with quantum traffic: route.
"I hate to advocate drugs, alcohol, violence or insanity but they've always worked for me" - HST
Yes and no. Let's step back and cover what is currently done:
Typically you generate a public/private key and give one out to the world (the "public" part, though in most systems that's an arbitrary distinction). The reason you do this is because it's "safe" to give out the public part (no one can decrypt your messages with it) and it gets around the horrible problems inherent in trying to move a key around that *can* decrypt your data (such as those used in symetric key systems). Now you could just stop there, and encrypt all of your data using the target's public key, but it turns out that that's fairly computationally expensive.
In order to speed up the process, you can just use the public key to encrypt a random, one-time session key that you use as the input to a (much faster) symmetric key algorithm such as IDEA, blowfish, twofish, DES, 3DES, etc. Now you have a fast communication path and, as long as the symmetric key system is believed to be at least as strong as the asymetric key system, you have not lost any security.
Now, if symetric key is so much faster, why don't we just use THAT? Well, we would, except that it's a pain to get the symetric key to the target without compromising it. You could, for example, send it via U.S. Post (slow, and not 100% reliable), send it over a private communication channel like a leased line (expensive, not secure), etc. There are other ways too. For example, you can NOT send the key, but have an out-of-band agreement as to how they are generated. For exaple, you might agree to use a pseudo-random number generator (PRNG) wiht a particular seed on a particular date, generating a new key each day. That's not too bad for some purposes, by typically it's not strong enough for truly important information, as PRNGs tend to have their own flaws, and anyone who finds out what you're doing essentially has every key you'll ever use until you exchange a new seed.
What quantum encryption changes is this: it gives you a secure channel over which to communicate (usually at low bandwidth), so you can use it to move a key for symmetric key encryption, and then perform your encryption with that. If anyone evesdrops on the connection, you are guaranteed to know (because the data will be changed, and presumably you've built in appropriate checksums so that you will realize that you now have line noise), and you won't use that key (providing trivial denial of service, which is why this isn't good for non-physical communications).
Quantum computing essentially replaces asymetric key encryption for short, physical links in terms of providing a secure way to exchange symmetric keys. If it gets up to the point that high volumes of data can be moved through the quantum link (which the article is not describing), then you can just move a one-time pad through the link, and your encryption algorithm will be a simple xor.
When an invention's time comes, the invention comes. The telephone was invented almost simultaneously by both Alexander Graham Bell and Elisha Grey, who arrived at the patent office only a few hours too late. The phonograph was invented by Thomas Alva Edison at around the same time as the gramophone was invented by Emil Berliner. The filament bulb was invented by Thomas Alva Edison only one year after it had already been invented by Joseph Swan {and unfortunately still has not been banned}. A public-key encryption algorithm was invented in the UK in the 1970s, but kept under wraps by the UK authorities; it was later discovered independently by Rivest, Shamir and Adelman in the USA. Details of the UK invention emerged shortly before the US patent expired.
Given all of which, I think it's reasonable to suppose that when the time for quantum computing arrives, quantum computing will arrive. With even the current state of communication systems, and assuming that communications will continue improving over time, it would be damn nigh impossible to suppress the facts.
Je fume. Tu fumes. Nous fûmes!