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Growing Diamonds for Better Information Security
hip2b2 writes "NetworkWorld is running an article that describes how a University of Melbourne research group is developing technology to make fiber optics communications more secure. The technology is based on Quantum Cryptography principles and requires than absolutely only one photon gets sent at any given time. Today, fiber optic systems do not send one photon at a time. They only approximate it. This makes current systems unsuitable for their secure communications technology. Therefore, the group uses artificially grown diamonds to achieve this."
Here's the actual University of Melbourne article from four days ago.
Common sense is not so common
Er, "artificial" diamonds are just as real as "real" diamonds. It's a face-centered cubic carbon crystal lattice whether transported up from the mantle by geological forces or manufactured.
DeBeers will give you all sorts of fud saying that they will eventually have a process for telling the difference between the two, but they won't. Ever.
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BMO
There are several ways to tell the difference between lab- and geologically made diamonds arising from the lack/presense of structural and chemicalimpurities.
Remember the four 'C's: cut, colour, clarity, and carat weight. Lab-made diamonds can now be produced with rather high carat weight, necessary to cut them into gemstones (30-70% of the material is removed in cutting). They are now being grown large enough to be cut as well as any diamond; so 'cut' and 'carat weight' can be the same for the two.
The crystal structure of laboratory diamonds can be made with few gross imperfections, causing the clarity to be quite high. In general, the types of lattice imperfections, decreasing clarity, are rather different for lab and geological diamonds, making it not too difficult to distinguish between the two when there are structural imperfections present. Only the very best crystals in each class would be hard to identify---those without many obviously lab-made or geologically-made lattice imperfections.
The 'c' that makes lab-diamonds not very marketable today is 'colour.' The colour of a diamond arises from natural or artificial chemical impurities. Natural diamonds have an enormous variety of colour because of the variety of (chemical) environments in which they are formed. Artificial diamonds tend to be produced in labs where they are all produced similarly, without much variety in (or any good way to control) the colour. Indeed, most artificial diamonds today are an intense orange-yellow colour because of the nitrogen introduced during processing. A natural orange-yellow diamond could be very expensive because of its rarity, but the market for such 'fancy' diamonds is substantially smaller than for white/clear diamonds.
Anyway, it will be a long time before you couldn't tell the difference. And when lab-diamonds can be made with arbitrary colour, size, and crystal strucuture, the easy way to tell the difference is the LACK of any natural imperfections.
The point of building/using a quantum channel (the fibre line) is to solve the key distribution problem, it cannot be used to send data. Why? Firstly in the protocol used for checking for eavesdroppers you end up discarding around 3/4 of the photons sent, with no way of predicting which ones, and secondly you really need to be sending random data to make it completly secure. The result is both parties end up with a random key, and you know with absolute certainty that no-one else has it. Compare with your "use a courier and a CD" method (which some places do currently use), where you cannot know if someones managed to make of copy of the CD during transport, and also cannot guarantee CD has been kepy securly (during the year (in your suggestion) its kept).
Once you have your key though, the can use the Vernam cipher (one time pad) which is provably unbreakable, to send the actual data over a standard telco line, copletly securely.
I suggest you read about quantum cryptography more (wikipedias probably good).. pretty much the entire point of it is that you cannot just intercept and resend the photons without being detected. What you can do, if each laser pulse actually contains two identical photons is split one off and keep/measure that, without being detected. Hence the importance of single photon sources (which this research is in).
I don't know that I'd call diamonds an "investment" when the price is related in large part to the De Beers monopolistic practices. Should their monopoly fade, so too will diamonds' sparkle as an investment commodity fade. Hmmmm, I think I'll google around now for info on whether diamonds actually offer any sort of return on investment. As an aside, if the diamond is attached to a ring attached to a girl, it's 100% certain to cost you money in the long run ... well, in the short run too.
OK, quick googling: no dice. Except this is amusing and interesting. Apparently, without monopoly control, "There are really enough diamonds to give each man, woman and child in the United States a whole cupful." Cite. That doesn't bode well for the time the monopoly falls.
What changed under Obama? Nothing Good
As I understand it, but of course I am not a quantum crypto researcher, the idea is that this is secure because your premise of "If something can be read, and written - it can be copied." does not hold true.
The idea is that with these quantum particles you are transmitting the data by means of the "spin" property of the particles, rather than simple on/off pulses. The key point is that by measuring the spin you affect it and change it completely, meaning that anyone at the other end will know, because all their data will be garbled.
This method doesn't stop someone from listening in, but if they do so, all parties involved will know and can just avoid using the compromised keys. If, however, you don't listen in on the key transmission, the data can then be sent encrypted and you are out of the loop once again.
Of course, as someone said, a repeater makes this all pointless.
No no and no. I'm not meaning to be harsh but everything you said is misunderstood. The point is not to achieve security by doing things really slowly, the point of quantum cryptograhpy (wikipedias quite good) is that if anyone intercepts your photons/information, you know about it. So you can resend the information, using a differenet channel, whatever. It is very important in crypto to be able to guarantee that no-one else has your key.
Entirely true in the classical, everyday world, and you'd think so on small scales (individual photons/atoms) too.. but actually wrong. Quantum states cannot be coppied (no cloning theorem). This is where the security of quamtum cryptography lies. There's nothing to stop someone from eavesdropping on your fibre, but if they do intercept anything you know about it. The only way they can get information without you knowing is if you accidently send the information twice, ie two photons in a pulse instead of one. Thats where this research is useful, its anything but pointless.
I don't see how transmitting single photons at a time as opposed to the millions used today would give a speed increase, the fastest quantum cryptography demonstrated so far achieved a rate of 500b/s, compared to 500Mb/s for normal fibre communication. It's only real purpose is cryptography.
Current systems use attenuated lasers.. basically you shine a laser onto a pair of very small holes, and theres only a very small chance of any photons getting through. So on average you'll get between 0.05 and 0.5 (determined by the size of the holes) photons passing through in one pulse. This is all on average though, sometimes you'll get 0, sometimes 1, and rarely 2 (or more). Hence "approximatly" one per pulse.
(e.g. the 'buyback' may not be cash on the barrelhead, but instead a credit towards a more expensive diamond, making it an upgrade, not a refund. This is very profitable for the jeweller, enabling them to effectively sell you the gem you can afford now vs. a decade ago, to collect additional revenue, while recouping the full 'buyback' price by selling the 'returned' diamond to a new customer at full price)
Appraised price is meaningless and unattainable, making diamonds a poor investment for those outside the trade.
In a way it has, temporarily. All public key encryption relies on the difficulty of factoring primes (or something very similar). It is not proveably secure (unlike quantum cryptography), and in fact no-one has even proved that factoring primes cannot be done efficiently classically, we just don't have a way yet. One of the main reasons for interest in quantum computing is its ability to factor primes (thus breaking public key encryption). So in a way quantum cryptography is a solution to an anticipated next generation problem. Although people who already use one time pads (military, big banks.. people for who 'difficult-to-break' isn't enough) would almost certainly find using QC better than using secure couriers of some sort.