> Blah wrote quite an excellent post. In fact, I've met few physics PhDs > which would have been able to respond so well. So needless to say, my > curiosity is peaked concerning who Blah is in "the real world". (Tim May,
Thanks. It's nice to run into physicists and as a physicist, you'll appreciate the followup to mr. choate's response, since what he suggests is essentially contrary to special relativity. As for myself, I'm a nuclear physicist by training (weak interactions - experimental searches for nucleon substructure in nuclei, parity violation in nuclear interactions, etc., but no longer in an academic environment. I read the archives from time to time to see what's going on, since I have an interest in the political end of technology. > I believe, is trained in physicsist, but there's no way someone out of > school for so long is going to voluntarily remember what's in the last > chapter of Schiff. Also, they didn't know a lot of this stuff back in the > horse-and-buggy days when May was in school...) > Anyway, I DID want to ask ole' Blah what he thought about the following. > (Now Choate, Shaddup and pay attention: "Slap Slap Slap!") Since I read through the archives somewhat irregularly, and don't really try to figure out the personal dynamics, I've often wondered why mr. choate gets so much abuse, since he's really pretty sane in comparison to the crackpots that post in the sci.physics.* newsgroups. However, I think I may have a hint at this point. > As a (fellow) trained physicst, do you actually believe that quantum- > encrypted signals are truly secure as a byproduct of basic physical law, > or do even YOU believe that QM is merely a "useful calculational tool", > so that (by inference), Quantum-encrypted signals may one day be > interceptable without either Bob nor Alice knowing that a third party > is listening? I have to split that into several parts. First, I think quantum mechanics has to be fundamental. I consider that the reason it's a useful calculational tool, so I take the useful part as a consequence of being correct. It seems rather bizarre to adopt the view that the universe is classical, and that quantum mechanics was developed as an an incredibly successful approximation to the classical model that didn't work. So far, I find all of the attempts to rationalize quantum mechanics into a pseudo-classical framework (e.g., bohmian mechanics), to have serious shortcommings in that those models pick and choose what they want to "explain" and ignore what they can't. If anything, I'd classify myself as being at the opposite end of the spectrum than "shut up and calculate". The "shut up and calculate" approach is ok if what one wants to do is calculate without going out on a limb, but practically all of the physical intuition comes from knowing what it means to to have quantities which are "unobservable" or indeterminate, so I'd have to say I gave up the idea of any underlying classical realty. Second, the quantum mechanics part of a secure quantum protocol is only one aspect of a secure quantum protocol. I think richard hughes at los alamos has already demonstrated that secure quantum encryption is a reality, if one uses a shared secret to inititialize the session. On the other hand, I'm rather dubious about a completely secure protocol which does not require a shared secret. Third, the major impediment to implementing such a system would be not a technical difficulty, but a political one. Administrations like the current one certainly have no interest in the widespread use of unbreakable encryption. The general public is lacking both the interest and technical ability to disinguish between advertising and technical merit. In fact, the general public doesn't even seem to believe in punishing outright fraud when it affects them, so I wouldn't hold my breath for such a system to appear. > As for myself, I think I've made my bias clear, but I wouldn't call it > 'certainty' by any means. I think your safe in your bias. Nature can't be so perverse as to go to the effort of of creating a classical world and then covering it up with a convoluted scheme to look like quantum mechanics as some sort of cruel joke. ---- As a side note on a different issue. The new scheme for crowd control utilizing microwaves, should be relatively simple to defeat. Covering garments made from fine metallic mesh screen, grounded through something like those little covers with the metallic grounding strips that surgeons wear ought to do it. Any (fairly good) conductive fabric should work. Since I have no idea what frequencies are involved, it's hard to say how corse a mesh one could get away with using. As a comparison, however, the typical microwave oven generates on the order of 1.5 kW at 2 GHz or so, and the mesh on the door sheilds the microwaves well enough to stare at what's inside. Faraday cages in radar labs are usually made from metallic screen. For that matter, having a line of people carrying a few rolls of aluminum foil ought to be a pretty decent reflector which could be used to more or less, redirect the microwave radiation at will. -- later
