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Researchers Simplify Quantum Cryptography
Stony Stevenson writes "Quantum cryptography, the most secure method of transmitting data, has taken a step closer to mainstream viability with a technique that simplifies the distribution of keys. Researchers at NIST claim that the new 'quantum key distribution' method minimizes the required number of detectors, the most costly components in quantum crypto. Four single-photon detectors are usually required (these cost $20K to $50K each) to send and decode cryptography keys. In the new method, the researchers designed an optical component that reduces the required number of detectors to two. (The article mentions that in later refinements to the published work, they have reduced the requirement to one detector.) The researchers concede that their minimum-detector arrangement cuts transmission rates but point out that the system still works at broadband speeds."
Either this post is first or it isn't. I won't know until I press submit.
Women are like electronics: you don't know how damaged they are until you try to turn them on.
Anyone care to explain why anyone should use this? So it's 100% random...why cares? So equation and clock based pseudo random based encrptions can technically be predicted cuz they're not 100% random. But nobody ever knows the exact equation AND exact millisecond it was calculated to generate the key so noobdy can predict it. I don't think it's any better. It's just a product they're pushing with some ridiculous statement like "but it's better cuz it's completely random!" and never back it up with any facts about it truly being harder to crack.
Google's Super Secret Search Algorithm: SELECT @search_results FROM internet WHERE @search_results = 'good'
Is there anywhere in the world actually using this sort of technology? Is it used in the military at all?
With this simplification, thousands of cats are saved from having to deliver code keys.
Every time I hear about Alice and Bob, I now think of this
The sexy part is that if there is a third party who tries to eavesdrop, the attempt will both fail and can be detected by the two communicating parties, and that the security of quantum cryptography has nothing to do with the lack of ability to factor large numbers, but is instead based on physical principles (quantum mechanics). Of course, the sensitivity to eavesdropping means that the system is probably vulnerable to a denial of service attack, depending on how the two communicating parties relate to eavesdropping.
Otherwise, you are perfectly correct. Many cryptographers, including Bruce Schneier, believe that quantum cryptography is a solution to the wrong problem. Nowadays, most probably, the least secure part of your communication system isn't in your key distribution scheme, but is somewhere else --- like in social engineering, or the computer systems which deal with the decrypted cleartext.
Describing the rate as "Broadband Speeds" is about as useful as describing the performance of a supercar as "roadworthy" (there's your car analogy).
For reference, in Australia not only does the incumbent Telco consider 256/64kbps to be broadband, but they also describe it as "Fast".
What speeds are they calling broadband? 200Kbps?
It's a summertime Northern Hemisphere and a wintertime Southern Hemisphere. Slice the world the other way and its daytime in one hemisphere and nighttime in the other. And its always dark down here in my parents' basement.
You can achieve comparable security using Byzantine methods to split a one-time encryption pad into relatively secure fragments. Since the fragments can be reordered and then randomly embedded in the data, you can achieve everything boasted for quantum encryption but using methods tried-and-tested.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
There is only one cryptography scheme with proven secrecy, and that is the one time pad. Even if you assume no errors occur in its implementation, no physicist can guarantee there will never be discovered a way to eavesdrop on transmissions that use Quantum Cryptography. In contrast with the one time pad a Mathematician can more or less prove, at least to the extent you can prove anything at all, that eavesdropping is only possible if the implementation is flawed.
In practice none of this is relevant since the hassles associated with correctly implementing either QC or a OTP are sufficiently large that for most applications they are both inferior to public key cryptography and symmetric ciphers. There are some exceptions, but the only way you could possibly justify describing quantum cryptography as "the most secure way to transmit data" would be by ignoring so many aspects of information security that it will have no relevance to practical applications.
...would suck.
expandfairuse.org
I'm all for R&D into pure science, and I'm not bagging the concept of quantum cryptography, but why does this need to be a commercial product?
Is there really anyone out there paranoid enough to need/want this besides various three-letter agencies? Maybe this is proveably secure, we think, but what is more likely - Someone finds a loophole in the very weird world of quantum mechanics that makes quantum cryptography as we know it obsolite, or someone figures out a way to find prime factors of obsenely large numbers in a reasonable time.
This article is about how it may be possible have a quantum crypto setup with a bandwidth of maybe 1024kbps by spending only $20k-$50k on one component to the system. I bet there is a lot of other components.
Compare this with a basic commodity PC, which can could encrypt 1024kbps using AES with ridiculous ease.
You are comparing apples with oranges. The bit your mathematician can "prove" is only part of the problem quantum encryption aims to solve. Ie quantum encryption also includes key exchange (and in fact typically uses a one time pad for the data transfer).
You can't simply ignore the key exchange problems on the mathematicians side.
Perhaps the laws of physics that are supposed to protect quantum encryption will turn out to be false but based on our current understanding there is no better way to do it.
How is your mathemetician going to distribute his one time pad?
Boffoonery - downloadable Comedy Benefit for Bletchley Park
You do realize that QC is just a method of securly distributing a one-time-pad between two endpoints, right? They don't use the photons to send the message data, that gets XORed later and sent via normal channels. So if everyone is wrong about quantum mechanics translates directly to "the OTP implementation is flawed". While OTPs are hard to implement (Where did I put that onionpaper again?) the whole point of developing QC is to get to the point someday where it IS practical/hasslefree to distribute the "pad". Ever faster and over longer distances.
"You saved 1968." - Ms. Valerie Pringle to the crew of Apollo 8
For a really really good look at security, try to track down the earliest black+white TV series of Mission Impossible - (almost no gadgets, lots of neat social engineering).
Andy
Google it...
or check this: http://it.slashdot.org/article.pl?sid=06/12/13/1458238&from=rss
"Knowing everything doesn't help..."
Actually... This could have been the first post, not the first post, or both. And even though you had pressed submit, you probably wouldn't be able to find out anyway.
Fact: Everything I say is fiction.
That's a relief. I was worried there for a while.
FAQs are evil.
As someone who has did several years of research in QKD (aka Quantum Cryptography), implementations of QKD that only use one detector have been around since the 90s, and the awareness that it is possible to implement them have probably been around since the 80's. I'm too lazy to get a source if someone else wants to get the karma. So this article isn't entirely news and is there is probably some artificial hype added to it.
QKD works by making measurements of the Quantum basis that a sender sent, and generally in optical schemes you need two or four photon detectors on an optical interferometer to detect each basis. If you reduce the number of photon detectors to one, you can only detect one basis. However, the mechanisms involved allow you to still recover data and keep the key exchange secure. It isn't a fundamentally novel concept to anyone who knows the basic theory of implementing a real world QKD system.
I haven't worked on QKD in a few years, so my knowledge of the theory might be rusty, so feel free to correct me if anyone knows better.
... for making the comment I was about to make. :)
I see someone didn't read the instructions and looked at the light while posting.
Get a web developer
The one-time pad requires a shared-secret key in order to be able to encode and decode encrypted messages. Sharing the key securely becomes a huge logistical problem.
Quantum cryptography promises, through quantum theory, that anyone trying to skim data from a secure channel ultimately corrupts it. So by measuring the noise level in the channel you can detect an eavesdropper.
A typical Quantum cryptography scheme requires two channels. One of the channels is a classical channel, like the internet, which is used to exchange the encrypted message. The other is a low noise quantum channel, which is capable of exchanging some kind of physical entity with information about the key encoded in its configuration. An example of such a physical entity would be a collection of polarized photons.
The rough idea is that you exchange the key over the quantum channel. If while doing that your "noise level" rises beyond a certain threshold, you abort the transmission. Otherwise the key to your OTP is now shared and you transmit your encrypted message over the classical channel.
I didn't miss your point, science isn't provably true and quantum mechanics may someday turn out to be wrong, exposing a loophole which allows for eavesdropping. But quantum cryptography isn't as much of a cryptography scheme as it is a transmission vehicle.
Still, if you want to find a flaw with quantum cryptography, you don't have to look very hard. Quantum cryptography assumes that your man in middle just wants to read data out of the channel without breaking the link. It is easily defeated if someone can make themselves into a relay.
i.e. Quantum cryptography is defeated if an eavesdropper cuts both the quantum and classical channels and inserts herself into the middle:
Sender ===>>=== Attacker ===>>== Receiver
where she pretends to be the receiver to the sender and rebroadcasts the message as if she were the sender to the receiver.
...quantum cryptography now requires 30% less cats and 46% fewer radioactive isotopes.
Random Thoughts From A Diseased Mind (Not For Dummies)
Article Summary states "Four single-photon detectors are usually required (these cost $20K to $50K each)"
sounds expensive.
except, the real article states: "Bob uses four single-photon detectors, costing approximately $5,000-$20,000 each."
still pretty expensive, but it sounds like you could have a working one of these for only 10k in detectors!
I was just discussing entanglement swapping with my supervisor the other day, actually. Neat concept. Roughly, person A has two entangled photons, A1 and A2. Person B has similar, B1 and B2. They both send their 1 photons to C. C entangles A1 and B1 and because of this, A2 and B2 are now entangled. This can then be used to generate a bit of a key.
We were actually discussing it in the context of producing entanglement between ions (good for storage/memory) and photons (good for transmission), since in the real-world it's unlikely actual repeaters will receive photons from both parties at the same time so that the entanglement can be swapped.