The internet all together is pretty impossible without cryptography ecommerce is one big one but no banking no binary security all the stuff will be public all your base are ours. John what are you going to do for a living next.

"Quantum computers are firmly in the world of engineering possibility, although the process of building a viable machine is still a long way off."

Oh? That would not necessarily be the case if a Quantum computer is SMARTer Software rather than newer Hardware. Indeed, PreLogic would surely dictate that such would be the case for one normally, QuITe naturally works out the Processes/Methodologies/Concepts first, for Machines to Follow as Servants of Man's Imagination/Innovation/Original Gifts.

"The difficulty of factoring the product of extremely long prime number...."

What? I can do that in less time that it took to read that sentence. Let's see.... OK! Prime number times anything gives the product! Voila!

No wait - Let's go the other way. Prime number divided by itself equals 1. Voila!

The english language all together is pretty impossible without decent grammar writing is one big one but no sentence structure no making sense all the stuff will be unreadable all your base are ours. Alan Donaly what are you going to do about your education.

"John what are you going to do for a living next."

He's probably going to enjoy it now, Alan, if the Code is Wild and Free to Use. IT is Self- Policing and FailSafe at Creation Levels.

Now QC is something I'd rather live without, as I would be out of a job: IT Security in a Banking Institution (guess what we use), and it would certainly collapse *everything* I could make a decent job in. Not to mention it would make possible for any kind of public-key crypto to be cracked. Most security depends on public-key, this would bring that crashing down.

It doesn't crack symmetric ciphers, though; but key distribution is usually done with public-key stuff. Ow.

"Now QC is something I'd rather live without, as I would be out of a job: IT Security in a Banking Institution (guess what we use), and it would certainly collapse *everything* I could make a decent job in."

Daniel Ballado-Torres,

Yes, It does/is doing all that you say, Daniel Ballado-Torres, and of course, so much more, which for now there is little need in saying, given what it does/is doing/can do.

Living without Quantum Communications is NOT an available option...... so the SMART Money in an Immaculate See should automatically cover IT to ensure Favoured Status in an ESPecial Relationship otherwise it will surely Founder on the Rock of Denial rather than Flourish in the Flowering of New World Order Systems Communications.

"Not to mention it would make possible for any kind of public-key crypto to be cracked. Most security depends on public-key, this would bring that crashing down." ...... You certainly have a firm grasp of ITs limitless, latent capability.

One would then presume that such XPerts as there may be in Quantum Communications, would be a Most Valuable Resource Asset to be booked in rather than to be ignored, Creating a Competing Liability in a Market uncovered. After all, let's get real and admit that an unlimited line of credit is as easily stopped as it is created should it be the entry key into such markets.

And it is not as if it is possible to lose anything is it, whenever it all passes through the System anyway.

Public key crypto which depends on factoring a number made from two primes will die in an instant if somebody cracks the maths to do it, after this happens we will have to find a better way of doing it, generation of long streams of symetric keys in a predictable (to those who know) way, a truly random key as long as the data is (and will remain forever) uncrackable.

Incidentially, this could be used to crack symetric key cyphers if you can brut force billions of keys quickly and check the decrypted value for valid data, if you have 1Mb of http data encrypted with 3Des, keep trying keys until you get ascii only, once you have, you have the session key, totally impractical with a silicon chip computer, but not with QC (perhaps we should start looking at much longer session keys?).

Another solution is dongle/token based crypto, assuming the changing key rotates quickly and unpredictably, we would need to extend the technology (multiple server capability not based on RSA style maths), but physical keys biometric protected USB interfaced tokens could give that security today.

Euler totient based crypto has done us proud for a long time, but who's to say that it hasn't already been broken? even simple maths like the classic prime=(41 + (n*n) -n)) works for a lot of low values of n which shows that there could be a pattern in the chaos (and a shortcut to Shor starting values could make it breakable in seconds on a basic PC and maybe real-time with dedicated, todays technology chips).

QC is new and facinating, but perhaps it's the solution to the prime problem and not the problem itself?

I would be interested in other applications for QC other than trying to brut-force crypto maybe calculating weather patterns after the worlds topography and temps can be input as a massive number of variables, which given our screwed up weather, wouldn't that be useful?

I don't understand what's so new about this. There are public rainbow tables for most of our e-commerce crypto algorithms and we could see mulitcore cpus with around 16k cores in the past used mostly for scientific and military applications. (this means some governments already see all the data)

Remember when the US government had "export restrictions" on products with usable key lengths (even though the idea was "invented", but not patented by a British scientist/mathematician working in the military several years earlier)?

"Export strength" encryption keys were crackable if you had incredibly large resources (NSA style) but were not practical for just about anyone else.

Even if quantum computers capable of cracking the keys used in e-commerce are ever created (which I personally think will never happen) I suspect the complexity and sensitivity of the equipment necessary would be so expensive as to be in the realms that again only the US govt or very, very wealthy corporations could afford.

I am still yet to see any indication that quantum computers will be any more prevalent in 20 years than desktop cold fusion reactors a la Fleischmann-Pons are today.

@Cryptography :

For common crypto algorithms, it takes a cheap computer to create the encrypted messages and a very powerful (and expensive) computer to break them.

So everyone can create them but only governments can easily crack them.

As computing power gets cheaper, you increase the key length, to keep this state of affairs. If you increase the key length too much so that governments can't crack them, then Joe Public's low powered computer takes too long to create the messages. Hence the compromise.

Now, if you have cheap quantum computers, then it will be as cheap to create and break the algorithms, increasing key length, the same money will do both. And increasing key length no longer keeps the breaking out of reach, unless you make the creating out of reach too.

@cold fusion 2.0

Because, based on this articles (and lots of others), creating a useful quantum computer is now an "engineering problem" i.e. we know the theory and have a proof of concept, we just have to figure out how to build it at a reasonable price. And based on history, throw enough resources at it and these type of problems get solved.

Whereas cold fusion is a "theoretical problem" i.e. it can't be reliably duplicated and we don't know the theory behind it yet.

So quantum computing is several steps further on than cold fusion. And quantum computing will have lots of resources thrown at it, because crypto is (creating and breaking) very important to people with money, as is lots of other problems it can solve (e.g. weather forecasting, logistics)