RE: Scientific American on Quantum Encryption
What do you mean? By a physical fiber switch? That's certainly possible, though you'd need a very good condition switch to be able to do it. I'd bet if that switch switched a lot, the QCrypto channel would eventually be unusable. If you're talking about a WDM element or passive splitter or other purely optical component, then you'd need some kind of error correction (in the digital domain) in order to overcome the fact that many of the photons will not choose to go in the direction you want. In the long run I think we'll see some small proliferation, but given the level of integration and how well current coding schemes work, I'd guess this will remain a niche unless there's a major breakthrough in factoring. -TD From: "Trei, Peter" <[EMAIL PROTECTED]> To: "Eugen Leitl" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> CC: <[EMAIL PROTECTED]> Subject: RE: Scientific American on Quantum Encryption Date: Thu, 20 Jan 2005 10:47:38 -0500 I've actually seen these devices in operation. The thing that impressed me most was that the path need not be a single fiber from end to end - you can maintain quantum state across a switchable fiber junction. This means you are no longer limited to a single pair of boxes talking to each other. True, the SciAm article doesn't address a lot of issues, but the fact remains that this technology is interesting and important. Peter Trei > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Eugen Leitl > Sent: Thursday, January 20, 2005 6:17 AM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Scientific American on Quantum Encryption > > > > Scientific American has little clue, as usual (see their > nanotechnology > retraction). > > Link: http://slashdot.org/article.pl?sid=05/01/20/0358215 > Posted by: samzenpus, on 2005-01-20 06:35:00 > >from the just-try-and-break-it dept. >[1]prostoalex writes "Scientific American claims that > [2]advances in >commercially available quantum encryption might obsolete > the existing >factorization-based solutions: "The National Security > Agency or one of >the Federal Reserve banks can now buy a > quantum-cryptographic system >from two small companies - and more products are on the > way. This new >method of encryption represents the first major commercial >implementation for what has become known as quantum information >science, which blends quantum mechanics and information theory. The >ultimate technology to emerge from the field may be a > quantum computer >so powerful that the only way to protect against its prodigious >code-breaking capability may be to deploy quantum-cryptographic >techniques.""
Re: Scientific American on Quantum Encryption
Well, I think you've been a little too harsh on Scientific American. In the past a lot of the best articles were written by the pioneers in their fields. In fact, it's where I believe Wittfield and Diffie wrote a great piece on their work. And don't expect anyone (not even a math major) to go grab a quantum mechanics textbook and be able to get anything out of it. One would really need to have done the classical coursework in order to understand it (or at least to know enough to be spurised by it). And if you don't have the math then forget about it. Meanwhile, it IS possible to write intelligently on quantum entanglement, EPR and Aharnov-Bohm, and it's been done by Sci-Am, Penrose, Kaku and plenty of others. -TD From: Justin <[EMAIL PROTECTED]> To: [EMAIL PROTECTED] Subject: Re: Scientific American on Quantum Encryption Date: Thu, 20 Jan 2005 15:23:35 + On 2005-01-20T12:16:34+0100, Eugen Leitl wrote: > Scientific American has little clue, as usual (see their nanotechnology > retraction). How could they possibly get clue? Scientists don't want to write pop-sci articles for a living. It's impossible to condense most current research down to digestible kernels that the masses can understand. SciAm should close down, requiring those who care about science to learn enough about it to read science journals. Professors who can teach a QM course well in a semester are rare enough. I doubt any one of them could write a 5000 word article on quantum entanglement that would be intelligible to the average cretinous American who wants to seem smart by reading Sci-Am. If they want to be smart, they can start by picking up an undergrad-level book on QM. But that requires much effort to read, unlike a glossy 5000 word article. Journalism should not be a college major. Journalists in the main know little about how to write and interview, and less about the topics they write on. They don't understand that being able to write (and in many cases even that ability is in serious doubt) doesn't qualify them to write on any topic they choose. Many journalists aren't qualified to write on anything, not even journalism. -- "War is the father and king of all, and some he shows as gods, others as men; some he makes slaves, others free." --Heraclitus (Kahn.83/D-K.53)
RE: Scientific American on Quantum Encryption
Eugen Leitl wrote: > On Thu, Jan 20, 2005 at 10:47:38AM -0500, Trei, Peter wrote: > > > I've actually seen these devices in operation. The thing > > that impressed me most was that the path need not be a > > single fiber from end to end - you can maintain quantum > > state across a switchable fiber junction. This means > > Very impressive. If they manage to keep the entanglement all > the way up to > LEO by line of sight it would be even more impressive > (anyone thinks this can be done at all?) > > > you are no longer limited to a single pair of boxes talking to > > each other. At the moment, the practical limit in fiber is around 150 km Getting to LEO is a *lot* harder - remember, you're throwing and catching one photon at a time - a beam that spreads wider than your detector is usually going to miss the detector. Peter Trei
Re: Scientific American on Quantum Encryption
On Thu, Jan 20, 2005 at 10:47:38AM -0500, Trei, Peter wrote: > I've actually seen these devices in operation. The thing > that impressed me most was that the path need not be a > single fiber from end to end - you can maintain quantum > state across a switchable fiber junction. This means Very impressive. If they manage to keep the entanglement all the way up to LEO by line of sight it would be even more impressive (anyone thinks this can be done at all?) > you are no longer limited to a single pair of boxes talking to > each other. What makes it very important is early beginnings of practical quantum computing. Will photonics and spintronics in solid state at RT play well with each other? Will error correction scale to large qubit register sizes? Will the algorithm space be large and rich enough to be practical? All very interesting questions Scientific American fails to raise. > True, the SciAm article doesn't address a lot of issues, > but the fact remains that this technology is interesting > and important. I agree that this technology is interesting and important, but not for what it claims to be used for. Quantum encryption right now is a tool to milk the gullible, and hence very much crypto snake oil. For these distances one-time pads by trusted couriers would seem so much more practical and so much cheaper. -- Eugen* Leitl http://leitl.org";>leitl __ ICBM: 48.07078, 11.61144http://www.leitl.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE http://moleculardevices.org http://nanomachines.net pgpIzevOdZDJw.pgp Description: PGP signature
Re: Scientific American on Quantum Encryption
On 2005-01-20T12:16:34+0100, Eugen Leitl wrote: > Scientific American has little clue, as usual (see their nanotechnology > retraction). How could they possibly get clue? Scientists don't want to write pop-sci articles for a living. It's impossible to condense most current research down to digestible kernels that the masses can understand. SciAm should close down, requiring those who care about science to learn enough about it to read science journals. Professors who can teach a QM course well in a semester are rare enough. I doubt any one of them could write a 5000 word article on quantum entanglement that would be intelligible to the average cretinous American who wants to seem smart by reading Sci-Am. If they want to be smart, they can start by picking up an undergrad-level book on QM. But that requires much effort to read, unlike a glossy 5000 word article. Journalism should not be a college major. Journalists in the main know little about how to write and interview, and less about the topics they write on. They don't understand that being able to write (and in many cases even that ability is in serious doubt) doesn't qualify them to write on any topic they choose. Many journalists aren't qualified to write on anything, not even journalism. -- "War is the father and king of all, and some he shows as gods, others as men; some he makes slaves, others free." --Heraclitus (Kahn.83/D-K.53)
RE: Scientific American on Quantum Encryption
I've actually seen these devices in operation. The thing that impressed me most was that the path need not be a single fiber from end to end - you can maintain quantum state across a switchable fiber junction. This means you are no longer limited to a single pair of boxes talking to each other. True, the SciAm article doesn't address a lot of issues, but the fact remains that this technology is interesting and important. Peter Trei > -Original Message- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Eugen Leitl > Sent: Thursday, January 20, 2005 6:17 AM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Scientific American on Quantum Encryption > > > > Scientific American has little clue, as usual (see their > nanotechnology > retraction). > > Link: http://slashdot.org/article.pl?sid=05/01/20/0358215 > Posted by: samzenpus, on 2005-01-20 06:35:00 > >from the just-try-and-break-it dept. >[1]prostoalex writes "Scientific American claims that > [2]advances in >commercially available quantum encryption might obsolete > the existing >factorization-based solutions: "The National Security > Agency or one of >the Federal Reserve banks can now buy a > quantum-cryptographic system >from two small companies - and more products are on the > way. This new >method of encryption represents the first major commercial >implementation for what has become known as quantum information >science, which blends quantum mechanics and information theory. The >ultimate technology to emerge from the field may be a > quantum computer >so powerful that the only way to protect against its prodigious >code-breaking capability may be to deploy quantum-cryptographic >techniques."" > >
