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Single-Photon LED: Key To Uncrackable Encryption?
nut writes: "The BBC are carrying this story of new type of LED so precise that it can emit just one photon of light each time it is switched on. It has been developed by scientists from Toshiba Research Limited and the University of Cambridge. It is described in the journal Science, although I can find no mention of it on their website. One of the applications of this is supposedly uncrackable encryption, due to the law of indeterminacy. This application is described fully in 'The Code Book', by Simon Singh, although the method was only theoretical at the time the book was first published."
- The line can still be hacked, because it is possible to put a TEE into the circuit, just as long as STDOUT looks like STDIN.
- It may be possible to hack elsewhere, al la Magic Lanten.
- It would be very succeptable to stray photons, including those made by quantum effects...
Or am I wrong....OS/2 - because choice is a terrible thing to waste.
That wouldn't do much for lighting your christmas tree
If you had an entire array of these single-photon lights, couldn't it add an eerie glow to an object? Hopefully we can nanoscale these LED's and make things glow eerily.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
So I guess these things aren't for flash lights :)
I *know* it's an LED, but the question is, can you run Linux on it?
And as far as I can tell, this is only a silly little theory. So far they've figured out how to emit one photon, but they don't know how to read it. I'm sure that this is gonna be HUGE...
Username taken, please choose another one.
>>"That's a security loophole and our device is going to plug that,"
We have never heard that statement before.
The article is unfortunately a little light on details. The application of these devices seems to be for sharing key material for an OTP. Seems that it could be considerably more practical than the quantum entanglement of particles methods previously discussed.
I'm glad we have finally surpassed Bulgaria in photon emitting technology.
a beowu... ahh nevermind
if you want people to think you know what you are talking about, just put ".com" at the end of everything you say.com
. First they build the Super-kamakamode[sic] that can detect a single photon, and now they have ablity to emit them one at a time to!
:P
And that doesn't even get into their cool anime and hot women.
But seriously, this is going to require a bit of work before it's totally practical for mass usage, right now they would have to use a huge photomultiplier tube in order to actually sense a single photon. I think it'll be a while before CCD or CMOS light detection is that good...
Or hey, maybe we'll all go back to vacuum tube computers
autopr0n is like, down and stuff.
Why do people always say, "The BBC are..."? The BBC is SINGLE organization and as a result the verb should be singular: is. This goes for any other organization you can think of as well: Microsoft, IBM, the federal government. "The BBC are" sounds so stupid. Stop the madness people.
The line can't be tapped, because if you intercept the photons, you can't re-create the signal. Read an article on Quatum Cryptography.
-Mark
Isn't that what they say about every encryption method when it comes out?
Man, I wish we could just set our nation's resource distribution slider to 100% for technology for, like, a week. Then we'd have all this great new tech to mess around with!
Of course, we'd have to switch the slider back to 100% social for a couple weeks to quell the riots that resulted in a week of no police, social services, or law. But... nifty new toys!
"Destroy science and religion. Science would re-emerge exactly the same; but not religion." - Penn Jillette, paraphrased
Are they referring to the Heisenberg Uncertainty Principle? What is the law of indeterminacy??
Those crazy Japanese. First they build the Super-kamakamode[sic] that can detect a single photon, and now they have ablity to emit them one at a time to!
:P
And that doesn't even get into their cool anime and hot women.
But seriously, this is going to require a bit of work before it's totally practical for mass usage, right now they would have to use a huge photomultiplier tube in order to actually sense a single photon. I think it'll be a while before CCD or CMOS light detection is that good...
Or hey, maybe we'll all go back to vacuum tube computers
autopr0n is like, down and stuff.
Hmm... I wonder what color that photon is? How can they send a single photon through a fibre optic cable and not loose it and still be able to detect it?
Yeah, so we have the law of indeterminacy preventing encryption cracking, blah, blah blah.
But if we are going to consider laws of quantum mechanics, we only have a finite (less than 100%) chance of detecting the photon. So the LED will have to emmit multiple photon so there is a 100% chance of detection.
But then the indeterminacy law breaks down, doesn't it?
Standard UK usage is to say "Avis are renting me a car", "parcelfarce are idiots", etc. Yes it is strange if you are used to the US practice of using the singular, but it isn't just for the BBC.
However, one has to wonder what kind of restrictions that will be placed on this. What would you be able to do with unbreakable encryption? Share information on human rights abuses with your friends? How about plan the destruction of a high-profile government building?
The point is, it's time to show a little responsibility in the academic community. Just like the scientists who go ahead with playing God with stem cells before the ethical ramifications have been fully explored, these researchers have unleashed an unholy nightmare on the world that won't be fully realized until it's too late. It's bad enough that al-Qaida used GPG to communicate and coordinate their plans to commit atrocities agianst the US, but how much safer would you feel knowing that now not even the NSA can decypher their communications? Or even intercept them? It sets a dangerous precedent, and I think they ought to fully understand what they are bringing about before they actually release a prototype.
Is your company running tools written by ma
I tried "law +of indeterminacy" encryption and other combinations on google, but it all came up blank. Does anyone have a link describing how to use this for encryption?
-no broken link
...next we'll have single-neuron Slashdot posters.
Look, the future is now!
Do the people who get first posts ever use correct grammar and punctuation? the phrase "I didn't just wanted" does not make sense. Perhaps you missed a comma?
And back to the topic on hand...
The laws of quantum mechanics dictate that it provides a way to guarantee that no-one has intercepted that key
Cool. That's half the insecurity problem solved. Or is it? In cryptography are most breaches caused by keys not being kept secure, or by algorithms being cracked?
When DES was released, didnt they say it would never be cracked? Well look what happened there. In fact, it's been done several times now.
Never say Never.
Follow me
I remember seeing a documentary on someone who managed to teleport a photon using entanglement. While I'm sure the equipment/setup/everything is much more expensive, it could theoretically provide an even better method of secure communication. While you might not be able to listen in without diverting the photon from its destination, it is possible to stop the photon period (also as one poster already mentioned, you can't allow for a perfect world, so its always possible for photons to be dropped [or appear to be dropped] requiring another photon to be sent out, and thus making the system again insecure).
Physics kooks annoy me. They do. The Alexander Abians, the Time Cube guys, all of em have always bugged me. They've always had the feel of someone who feels themselves too smart to actually do the research to understand something.
So the fact that I hold tremendous doubt in something the physics gurus all take for granted *really* bugs me.
But, I'm telling you. Sooner or later the guys pushing quantum entanglement(*nervous twitch* spatial PRNG *nervous twitch*) will meet up with the guys working on quantum encryption, have some kind of matter/anti-matter postulate collision, and I'll have this big goofy smile on my face.
I'm telling ya, neither work particularly well by themselves, but in the context of the other, both Quantum Crypto(states can't be copied) and Quantum Entanglement(states can be copied, at FTL no less) are completely borked. It's the only kook conviction I haven't been able to shake, and you'll have to email me personally if you want to suffer through my full kook reasoning on it(you can probably guess what it is). But I'm telling ya: Next few years, possibilities are getting shuffled.
Yours Truly,
Dan Kaminsky
DoxPara Research
http://www.doxpara.com
I've been following this technology with great interest. There seems to be a fundamental problem: it is point to point. Its applications will be fairly limited.
It seems to me, at least in terms of networks, that this would really be used to secure lines between networks, clusters, or individual computers. But on today's public Internet, this isn't really an issue. Of course, I would rather use this technology than to not have lines protected with quantum indeterminism.
Most security people are more concerned about platform security than link security. If this technology can be used to reinforce something used for platform security, then boo yeah! Otherwise, this is cool, but I'm not going to get a heart condition over it.
The only platform benefit I see is reducing the need to perform expensive computations to encrypt and decrypt data. Let the link take care of that and thus increase performance. Of course, how many nodes on the Internet only want to talk to their nearest neighbor? And how many routers and such are between them and their nearest neighbor? It might not even be possible to secure the link between a node and its nearest neighbor in most cases.
I doubt this technology will impact current Internet infrastructure all that much. We'll see.
Here's the Science Magazine Abstract
----Abstract-----
Electrically Driven Single Photon Source
Zhiliang Yuan 1, Beata E. Kardynal 1, R. Mark Stevenson 1, Andrew J. Shields 1,Charlene J. Lobo 2, Ken Cooper 2, Neil S. Beattie 3, David A. Ritchie 2, Michael Pepper 3
1 Toshiba Research Europe Limited, Cambridge Research Laboratory, 260 Cambridge Science Park, Milton Road, Cambridge, CB4 0WE, UK.
2 Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK.
3 Toshiba Research Europe Limited, Cambridge Research Laboratory, 260 Cambridge Science Park, Milton Road, Cambridge, CB4 0WE, UK; Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge, CB3 0HE, UK.
Electroluminescence from a single quantum dot within the intrinsic region of a p-i-n junction is demonstrated to act as an electrically driven single photon source. At low injection currents the dot electroluminescence spectrum reveals a single sharp line due to exciton recombination, while another line due to the biexciton emerges at higher current. The second order correlation function of the diode displays anti-bunching under a DC drive current. Single photon emission is stimulated using sub-nanosecond voltage pulses. These results suggest that semiconductor technology can be used to mass-produce a single photon source for applications in quantum information technology.
-----End Abstract-----
If anyone has access to Science Online (http://www.sciencemag.org) you can download the PDF reprint at this link: here.
"One touch of Darwin makes the whole world kin." George Bernard Shaw
The application refers to its use in quantum cryptography. It doesn't render the encryption process uncrackable, but makes it able to detect that someone is eavesdropping and/or has broken the encryption. With current methods, you can't tell if someone has broken your key and read your message. Using quantum cryptography, you can tell when someone has read your message.
(It all goes along the lines of you can't observe something without changing it. If someone along the way intercepts the message and observes it, they will change the message and you can detect THAT on the other end.)
Where the wind blows, the tumbleweed goes.
Goddamnit! This is the second time I've posted a story, had it rejected and seen it posted by someone else within an hour.
Shit.
Blaze a trail to the New World
If this thing gets somewhat more advanced you will eventually become able to use the classic "man in the middle" attack. And since there are no keys involved in the crypto, it will work if you have only a connection to the cable. Sure it will cause some extra errors, as you cannot exactly copy the state of the photons, but that will only lead to the session being restarted, wich will make the mitm attack even simpler.
;-)
I see only 1 advantage of using this over traditional electrical wires, you have to actually break the cable to get to the data, but that is also the case now with fibre-optics, so it really doesn't matter.
just my thoughts, are they good ones ?
It seems as though for this to work we would need fibreoptics that act as "Superconductors" to keep photons from being "Lost" on the way to their destination.
You can't take the sky from me
You are single person criticize grammar but get wrong youself.
> The BBC is SINGLE organization and as a result
> the verb should be singular.
If a human constructed it, a human can deconstruct it. That goes for everything, always.
It's 11pm, do you know what your deamons are up to?
Hey! Now instead of using my photon light from thinkgeek.com to light my path i can shine it on computer systems and log in or use the different colors on an ATM machine in order to get someone else's money! Not to shabby for only $30!
My $0.02.
AJ
-------
artlu.net
I guess David Allen (inventor of the photon light ) is kicking himself now because he's been one-upped when it comes to lighting technology!
More accurately, Quantum encryption IS OTP. The quantum part comes in when you generated the pad.
"We need the detection technology for single photons," said Dr Shields. "But most of the other elements are there. It uses standard telecoms cables.
This sounds like a promising breakthough, although I can't help but wonder how far off in the future the detection technology is. I can claim that I have the key to teleporter technology, object decelerator technology (big, fluffy pillows), but I still need object accelerator technology (a large enough catapult).
Then again *yawn* this object decelerator technology is so comfy... maybe I'll just take a nap...
Surely this doesn't make it properly uncrackable.
It prevents people from reading the message then passing it on, but not from reading then generating an identical one. Admittedly this is a problem with all mediums, but quantum mechanics aren't the final solution yet.
mick
Mod the other post I did as redundant. Seesh.
autopr0n is like, down and stuff.
quantum cryptography + one time cipher = uncrackable
one time cipher + shared secrets = uncrackable
AFAIK, these are the only two that are uncrackable. the latter is impractical because of the necessity of a large quantity of pre-shared random ciphers, and the former due to implementation (but not for long it seems).
What kind of applications will absolutely require this extremely strong crypto?
With the RIAA, the MPAA, MS's DRM OS and this, I can imagine: the whole collection of Britney Spears works protected by quantum crypto.
What a waste.
* shivers *
The one-time pad (Vernam cipher), however, is uncrackable. It has been used very heavily since it was first introduced (1917) and, beyond being arguably the simplest automated cipher ever devised, is still being proven to be completely 100% uncrackable. Unfortunately, since the key lengths are at least as long as the message, and the keys can only be used once, exchanging keys can be a bit burdensome. Quantum cryptography is basically concerned with ways of exchanging pads securely. If our current understanding of the Heisenburg principle is correct, then current quantum cryptography (in combination with OTP's) is 100% uncrackable.
The failures of previous ciphers, especially public-key ones, is due to underestimating the difficulty (or "intractability") of certain computational tasks, but no one would have ever claimed that they were COMPLETELY secure, just secure ENOUGH. The Vernam cipher does not rely on computation (beyond addition mod 2), and is completely uncrackable.
It's not about timestamps. It's not "security through obscurity". It's about fundamental laws of quantum physics. Try looking at these links.
There are 0x40000000 types of people: those who understand 32-bit IEEE 754 floating point, and those who don't.
If we replace M with E, things become even more dire. Like B, E will choose the wrong detector half the time, but it will choose the "wrong" half ("wrong" according to the verification stage). For a message of length n, there is thus a 1 - (1/2)^n probability that E will not be able to recover the message.
Note that quantum cryptography is not meant to be used to send normal plaintext messages. It is meant to be used to transmit one-time-pads. Generally you'd want these one-time-pads millions of bits in length.
Let's suppose you create a protocol to set up an uncrackable, 100% secure channel between yourself (A) and your friend (B). I (M) am a real bastard and want to annoy you by intercepting your key and having lots of fun. You send your friend a one-time pad with your LED, let's say 1kB (8 kbit) in length. Note that this key is thousands of times smaller than your average key would be, but my calcalutor chokes if I don't use an obscenely small number :).
There is a 3e-1000 chance of me sitting in the middle without being detected (of course this probability is exponential, so a sanely-sized keywould give me very little hope indeed!). So, you send your friend 1kB and darn! someone was eavesdropping. You'd think your application would alert you at this time ("hey! I can say with literally 100% certainty that someone is eavesdropping!"), but lets say your application is terribly stupid. So, you restart and send another key. Same thing! Another few keys, then a few thousand more, then a few googol keys here and there. Damn! You've been trying to get this channel started for literally billions and billions of eons, and still you can't quite connect because someone's eavesdropping! Determined, you keep on plugging away. Millions of universes have expanded and collapsed by this time, but you still it says someone is eavesdropping!
Of course the prudent thing to do would be to write your application so that it gives up once there has been found an eavesdropper with *100%* certainty. :)
Anyway, once you finally get a key sent without a man-in-the-middle, you use that key as a OTP for more conventional uncrackable (no probability involved here!) cipher. Presumably with each message, you'd attach and encipher a new OTP along with it (or just use your LED to exchange a new OTP).
Mankind did go tens of thousands of years -- until the 19th century -- without police, social services, and proper law (by "proper" law, I mean law which is just and extends to all citizens). Oddly enough, the 19th century was right about the time we started getting riots, too.
What is the source of this LED? Quantum Dots? Single Molecule? Doped Buckies? SAMs? Anyone know how they do it?
If it becomes viable, it will likely replace communications where DES, Twofish, AES and other symmetric-key cryptosystems are being used, e.g. ABM's (or ATM's for you yanks), a whole slough of other financial services, maybe cellphones and the like, and other "miscellaneous" purposes (maybe a new "Hotline" from D.C. to Kabul?)
Me and my friend have previous shared a secret key, which is a random string of bits, of length 10. Now I wish to send my friend a message, a bitstring which is also of length 10. I take each bit from the key, and add it to the corresponding bit of the plaintext, modulo 2 (think XOR), to generate my ciphertext. e.g. if our key is 1010010101111010 and my plaintext is 1011110110101010, then my ciphertext is 0001100011010000. The key is then destroyed (for high security, it's stored on magnetic tape, then physically burned once used), never to be used again.
Now, let's say you have intercepted a message from me to my friend. The message is 1100101010000100. The only things you know about the secret key used before are: (1) it has never been used before; (2) it as a random (and uniformly distributed) smattering of 1's and 0's. Now tell me: what was the original message?
Unless public-key cryptography, it is not prone to "key attacks" (since you have no public key to work with). Unlike other symmetric-key (aka secret-key) cryptosystems, you have no frequency analysis or algorithmic analysis to work with. So long as you don't know any of the bits of the key, it is literally uncrackable, and has been for the past 80 years.
So, then the question is, how do you and your friend decide on a key? It's not easy. The best way, so far, is to physically go to your friend's house, make sure no one else is around, generate a random bistring, copy it onto two tapes (your friend keeps one; you take the other home), and keep it safe until it's time to use it.
What quantum cryptography does is lets you send a key to your friend over a long distance. But, do to quantum mechanics, you and your friend will be alerted if someone has intercepted it.
Nothing's really changed substantially here. It's the same uncrackable cipher that's been uncrackable for the past 80 years. The only difference is that now you can generate keys with your friend over a long distance, without having to drive to his house.
Nifty... But it's still somewhat volatile and a lot can disturb it. I still doubt this can reliably be done in a "real world" environment
Call me sceptic :)
Sorry, this only gets 3/10 as a troll. I appreciate the attempt at humour but you contradict yourself all over the place, and are a bit *obvious* with some attempted analogies and factual inaccuracies. Plz make the satire a bit more subtle next time.
Look forwards to next attempt,
Phillip.
Property for sale in Nice, France
More accurately, Quantum encryption is OTP. The quantum part comes in when you generated the pad.
(No, not al-Qaida, the US Govt. who supports the worst terrorist state the world has known in the past 1000 years or so. That state being Israel naturally.)
Hey man, the cleaners called, they said they managed to get the semen stains out of your white sheet -- are you going to have time to swing by there and pick it up in time for the cross-burning and negro-lynching?
IMO a single photon doesn't qualify as "Light".
Calling that a LED would be like taking something that emitted single H2O molecules and calling it a tap!
Bah humbug.
Well, it's not *that* difficult.
You input energy X, enough to account for a single photon and circuit inefficiencies.
Where X isn't enough energy for more than one photon.
The problem with the detector is that it's possible to build detectors that register single photons, it just requires that someone builds one, and that shouldn't be impossible either. It's a function of creating an optic trap akin to a waveguide and lens such that the single photon has to fall into a set of paths which is appropriately matched with a CCD able to register single photons.
GPL Deconstructed
"Using a technique called "brute-force", computers participating in the challenge simply began trying every possible decryption key."
DES was not cracked. A single message, encrypted by DES, was decrypted by trying every key until they found the right one. That's not cracking the algorithm. Cracking the algorithm means you don't need the key to decrypt a message, or you find a significant shortcut to figuring out the key, etc.
Every algorithm can be brute-forced, in theory. Question #1 is how much work it takes. In this case "tens of thousands of computers" were set to the task. Question #2 is how long it takes with the available resources. The article doesn't even give an answer to that. But consider: if you really do have an adversary who can summon that kind of computing power against just *one* of your messages, but you only need your message to be kept secret for a week and it takes that adversary 4 months to crack it with his huge distributed network...well then your message is still secure for as long as you need it to be, and DES works just fine.
If, on the other hand, you need that message to be secure until long after the Sun goes out, then you'd just use 3DES, since DES has long been thought to have too short a keylength (56-bit) to be considered "strong." In fact it was criticized for this even when it was introduced in the seventies and there weren't 10000 P4's sitting about with nothing better to do than try a brute-force attack. So, knowing this, you use 3DES (128-bit key), and the rest of the world can spend its time marshaling every PC, Mac, PS2, and microwave on the face of the planet against your 3DES-encrypted 2001 tax return, and odds are it'll *still* be safe long after humans have evolved into glowing spheres of light. This is assuming that computing power continues to increase at the pace of Moore's law.
Cryptography is *plenty* strong enough; fantastic algorithms exist and no they're integrity is not at all called into question by the "DES cracking" the article refers to. The problem is with how cryptography is used in the real world. The problem *is* in keys not being kept secure and other things like that, not in algorithms being cracked (unless you're the DVD-CCA).
James
The use of a one time pad, with truly random keying material (even if it appears random, but is in fact periodic, no matter how long the period, it will eventually be cracked) is uncrackable. Each ciphertext has equal probability of deciphering to any plaintext. This, it is impossible to crack.
Actually, I'd rather call you a skeptic. What you said doesn't stink.
What's this Submit thingy do?
Maybe this article didn't go into detail because the technology is still classified.
A while back there was an article in the news about quantum cryptography using photon polarity to ensure that the photon cluster received was the same as the cluster sent.
There was also some mention of timing the clusters so that nobody could break in and create a man in the middle attack without being detected.
It's all pretty obvious if you think about it a little bit. Electronic security doesn't hold a candle to the security potential of optical communications.
(oh, and it's quite late here now... bugger...)
"The Code Book", at least the british version, does describe that this unbreakable quantum encryption actually had several sucessful attempts befor this special LED appeared. I believe it was sucessfully done though the air at up to one mile. I would quote but since I'm moving the book is packed up. If you don't own the book, go buy it. It's a very good read.
Stay away from the Single Photon LED Christmas Lights, I heard they sucked.
-- the troll you responded to
If that fails, then you can fallback on various identification procedures. One simple solution would be to get A to send B a signed datestamp (and maybe get B to send one to A just for fun) using RSA signatures or ElGamal signatures or the like. Another solution would be (in a similar vein) to use a Zero-Knowledge ID scheme, like Feige-Fiat-Shamir. Unfortunately all of these solutions depend on theoretically "crackable" mechanisms.
Anyway, usually your "insecure" channel is public, which allows for eavesdropping, but doesn't allow for impersonations. A classic example would be a telephone ("hey Barbara, why do you sound like a 14 year-old boy?"), though admittedly the telephone wouldn't be so great for automated cryptography :)
This application is described fully in 'The Code Book', by Simon Singh, although the method was only theoretical at the time the book was first published."
Uhm... I believe this is wrong. The book was issued in 1999, and it contains this sentence in chapter 8:
Moreover, one paragraph further we see:
One of us is wrong -- either I'm reading this from an edited version of "the Code Book", although nowhere does it say "second edition", or the original poster needs to re-check his facts.
If you open yourself to the foo, You and foo become one.
There is a difference between a grammatical error ("the BBC are") and a typographical error ("BBC is [a] SINGLE").
I'm sorry, I must say that for once scientists have charged ahead and decided that stem cell research is for the benefit of all humanity, and should be applauded! After the fucked up things scientists have given us (the nuke, et al) it's good that something which acts at the fundamental, medical level - not just a new toy - is being taken seriously enough that those with the knowledge are willing to risk going to jail to bring it to us.
"Ethical" ramifications are never hashed out. People just argue ad infinitum. How long, exactly, would you say they should wait? Until either everyone on earth shares the same religion or there is no religion anywhere? Until everyone is in exactly the same sociopolitical caste and there's no racism, so everyone agrees? Dream on. Stem cell research will do more to improve the lives of humans than anything prior. Just give it time to become available to everyone. Not developing it won't make anyone's life better. So why wait?
toeslikefingers.com - because
Want to see it again?
Of course current randomising techniques are pretty good. If we take the exactly of radioactive decay, sure, maybe you get a 50.08% probability of a 1, or a 0.013 correlation between consecutive bits, or something like that. Ehh, whoop-do-doo :)
Those horrid garbage-like PRNG's (a la C's rand()) are fortunately a thing of the past (for cryptographic purposes anyway, at least I hope so). So you can't deterministically "guess" the OTP. Radioactive decay should theoretically be pretty good for random numbers, once people figure out ways to get rid of the biases in their equipment.
The nice thing about OTP's is that small amounts of non-randomness (as long as it isn't due to deterministic algorithms) doesn't matter much. e.g. image you intercept a coded message, and you find out that the OTP was done using a biased Geiger tube. You figure that there's a 1e-337% chance that the message says "LET'S BOMB AUSTRALIA TOMORROW!" (as everyone knows, encrypted messages are always written in all-caps), a 1e-214% chance that the message says "CAN YOU SEND ME THE JOHNSON FILE?" and a 1e-65% chance that it says "9&Q&*>#N_A_ARRUA^", what would you guess the real message is?
In the real world, it would probably be even worse. As equipment gets better, you'd get more and more these plausible messages, each with ridiculously ridiculously low probability of being the real message.
I mean think of it this way. If the OTP were truly 100% random, then ciphertext of length n bits would have 2^n possible corresponding plaintexts, each with 1/(2^n) probability of being the original message. If your PRNG (again, as long as it doesn't rely on a deterministic algorithm) is, say, only 95% random, then some of possible plaintexts would be given a very, very slight boost in probability of being the original message, and some would decrease in probability. For your average e-mail message, say n = 10000, you'd still have way too much to wade through that it'd make the changes in probability negligible, me thinks.
You can spoof bob to alice and alice to bob and just intercept the signal and then resend it. FYI, alice= sender, bob= receiver. This encryption stops you from listening in, but you could just receive the signal, ie block it from bob and make alice think you are bob and then regenerate the signal and send it to bob and he would think you were alice. Or atleast so I would think.
One, I was--of course--joking.
Two, yes, I agree, it's far more humane to burden the rest of society with the cost of maintaining those unreformable few whose actions are so blatant, terrible abuses that one has to question their humanity, at all. I, like you, would rather an innocent mother and her child--displaced and homeless--go hungry, than a miserable mass murderer be given his fair end.
Now, if you want to approach the topic from the standpoint of whether the justice system works well enough to support the inclusion of such severe penalties, we'll have more to discuss.
If a corporation is a personhood, is owning stock slavery?
Recall reading about these things about 10 years ago. Many amateurs have built their own devices and actually it is not hard. All you have to do is do some little calculus for your led and get some other cheap electric equipment. It is not expensive either.
For like 20$ you can get a device that generates genuine randomness in a way that can be practically used. The theory for this "unbreakable" encryption pops up every once in a while. Generally in magazines where editors have no glue about crypthography. It's soon almost 100 years old thing.. Wake up.
The channel can be attacked, and the message read; it just takes conventional means.
Quantum cryptography is great when it works! Imagine what happens when Eve just sits on the line, (i.e. Eve observes all of the transmitted photons). Eve is effectively making it impossible for a decypherable message to pass from Alice to Bob.
What then are Alice's choices? I will give you a hint: To send the message Alice has two practicle options.
If the hint didn't do it for you,
1) Alice sends the encrypted messages using a conventional, non-single photon quantum, method.
2) Alice decides that the cost involved in Bob recieving the message is an uneconomical choice, and thus Alice will not send it.
Either way message is not sent with a single photon quantum encrytion scheme.
P.s. The man in the middle attack works with quantum crypto if multiple photons are fired because one photon from each burst can be diverted to Eves listening device.
-- Matt
In order to use this tech you will have to create a transistor that can *detect* a single photon.
echo '[q]sa[ln0=aln80~Psnlbx]16isb572CCB9AE9DB03273snlbxq' |dc
Quantum cryptography, even in it simplest form (scheme BB73, from Bennett and Brassard) is unbreakable, even using unlimited computational power, both classical and quantum.
. html for further references.
In short, you can create a key for one time pad (which BTW is proven to be the only unbreakable classical crypto scheme) in such a way that no-one knows it.
As for eavesdropping - you can detect if someone is eavesdropping / attacking your scheme during key exchange, so you simply can restart it. Restarting mean that the attacker can DOS your key exchange - i.e. produce noise so you won't be able to agree on the key. Thus you will not be able to encrypt any data. But you will not leak any, either.
What's more - there exist some solutions for the DOS problem - one can enhance the exchanged knowledge is a way that minimizes the chance of attacker to possess it too. But these are probabilistical schemes, not fully safe. And rather impractical as they require much redundancy and communication.
If you have mathematical background, see http://www.cs.mcgill.ca/~crepeau/CRYPTO/Biblio-QC
e-mail: karol at tls-technologies.com
www: http://www.tls-technologies.com
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I have read "The Code Book" but don't have my copy with me, so please correct me if I am wrong. The impression I got from the section on Quantum Cryptography was that single photons would be used to securely transmit a full length random encryption key, where an eavesdropper could be detected and/or avoided. This key could then be used in a type of encryption known as a Vigenere Square, which (according to The Code Book) has been mathematically proven to be unbreakable when used with a full length random key. In this way, the LED in the article could be one component of a truly uncrackable encryption system. You still need a viable means of long range transmission and detection to make it practical though...
Do you mean BB84? I haven't seen security proofs for other protocols yet.
But beware of any claims about quantum bit commitment
-Hein
This SPED (single photon emmiting diode - we may expect this name to become nearly as commonplace as LED one day) also provides a cool way to implement a true random number generator.
The basic idea is that, as far as we know, the only TRUE source of randomness in nature is the collapse of a quantum wavefunction. Basically, the state of a quantum system is really the superpostion of several "pure" states. When the system is measured (I won't go into what constitutes a "measurement", that's a never-ending debate), this superposition collapses into one of these pure states. Which state this will be is, as far as we can tell, entirely random. Only the probability of each outcome is known in advance. Besides this, all other physical processes seem to be deterministic. So any true randomness in nature must have its origin in the collapse of some wavefunction.
How do we exploit this? Fire a single photon at a beamsplitter, then measure whether the photon has been transmitted or reflected. The outcome will be random in a true sense, the probability of each outcome will depend on the beamsplitter. But, importantly, there will be no correlation between successive outcomes if the transmission : reflection ratio of the beamsplitter is 1:1. If our two detectors (one for transmission, one for refection) aren't perfect and lose a photon, we can always fire another photon, so this should even work with imperfect detectors, like a CCD.
This can now be implemented, all we need is a SPED, a beamsplitter and two CCDs. These can all be made pretty small, so might even fit on a chip, and hey presto! You got yourself a little hardware random bit generator. The only problem left is that the thing must be cooled to some pretty low temperaure.
I've always been of the opinion that a random number generator should be hardware, not software.
"...Look on my works, ye mighty, and despair!"
If a third party is eavesdropping, their interference could be detected and the process restarted (to generate a new one time pad that the sender and receiver know hasn't been intercepted).
Of course, one time pads are only uncrackable provided that they are generated using a truly random source, and are never reused.
Andrew Shields and others released a paper last year on possible use of normal FET technology in conjunction with a layer of "nanometer-sized quantum dots" for the detection of a single photon. I'm not sure that the method he demonstrates there could be adapted to commercial scale crypto, but it certainly seems to be a possibility.
I'm no expert, and Shields' comments on problems of attenuation in fiber transmitters may render the unique selling point of quantum crypto (that snooping can be detected) moot, but it still looks very promising for such a young idea.
Okay, so it's only an attack against uncareful implementations. The easiest way of explaining it is the case of tapping a fiber optic line. You splice th fiber optic line and let all of Alice and Bob's photons pass through your detector. You inject your own polarized photons back towards the transmitter when the transmitter isn't transmitting. (You need to predict the timing of the transmitted photons, but that should be relatively easy.) You look at the polarisation of the photons you sent out after they reflect of the internals of the transmitter. This should leak information about the polarisation of the photon just sent or the photon about to be sent, or if the system is transitioning to send a photon in a different polarisation. Most designers wouldn't think to put a single photon detector in the transmitter, becuase they don't expect photons to be comming back at the transmitter, or assume such things would be inoocuous. Of course, there's always a man-in the middle attack if you don't ahve a good signature algorithm.
A brief summary is that you have a detector that can be set up to correctly detect rectilinearly polarized light or correctly detect diagonally polarized light. One person sends single photons randomly polarized in one of the 4 directions the other person is looking for. Afterward, they figure out which photons were correctly measured and those mesurements are the key bits. Like I said, I explained it better somewhere else in this article.
Copyright Violation:"theft, piracy"::Anti-Trust Violation:"thermonuclear price terrorism"<-Overly dramatic language.
Not necessarily if there's external synchronisation, so that the recipient knows when a photon has been dropped. A dropped photon will then be as useless to a MITM as an intercepted (thus changed) photon. However, I'm curious why you want only one photon - how to you play with quantum entanglement if you've only got one photon?
The article was light on facts to say the least. Unless there's some form of Quantum Encryption which doesn't rely on quantum entanglement that I don't know of???
FP.
Also FatPhil on SoylentNews, id 863
thanks for the insightful comment. i'm sure the brilliant scientists that devised this scheme NEVER THOUGHT ABOUT THAT.
leave it to jdrogers to point out the glaring oversight. thanks man.
since i'm sure you know just as much or more about quantum electrodynamics than the people that came up with this.
loser.
...I almost spilled beer in my cornflakes! :-))
"I love deadlines - I love the whooshing noise they make as they go by..." -Douglas Adams
This is not Encryption. It is not about breaking anything. This is a channel that upposedly does not to allow evasdropping. A completely different thing!
Most ACs are not even worth the keystrokes to insult them. Be generically insulted and ignored otherwise.
Hello - there's a company in NYC and the Boston area actually designing quantum encryption technology for eventual products. They have a team of heavy-hitters in the quantum information world. They're called MagiQ Technologies, Inc.
I know their CEO, and it sounds like they're doing very promising work. They've been pretty quiet about their stuff, but think that it's an example of the real-world applications of this type of technology.
Gregg Favalora - CTO, Actuality Systems, Inc. - The 3-D Display Guys
Does it emit the single photon as a particle or a wave?
Give serendipity a chance.
I have the same reaction to this as I do to the articles about quantum entanglement.
How the heck are you going to get a single photon to go large distances without getting absorbed? Even in space, if the photon hits a single atom, it will get absorbed, causing an electron to be excited. When the electron "leaps" back to a ground state, emitting a photon, isn't this a new photon?
I would think that this would lose any previously known polarization. If I'm wrong, please explain how a photon retains its "identity" even after being absorbed.
Imagine that this isn't in space, but in the atmosphere. Plenty of matter to interfere with long-range transmission of individual photons. Fiber-optic cables? I dunno.
"Genius may have its limitations, but stupidity is not thus handicapped." --Elbert Hubbard (1856-1915)
there's been alot of progress in LED's as of late, when are we going to see low heat, high light emitting diodes that rival incandecent or florecent lightbulbs? they'd last a lifetime (well, 3 years), and can be of nearly any wavelength...
moox. for a new generation.
it is a TECHNOLOGICAL LIMITATION, it is NOT a fundamental law of physics as you seem to be implying. The only problem is that we need to find something significantly lighter than a photon to detect that photon.
Image the situation like this : we're trying to detect an elephant by throwing elephants at it. Is it any wonder the originial elepant will respond to our "measuring" ? That is the real reason for Heisenberg's principle.
The second we detect an indirect way to detect photons (let's say we detect the gravitational surge) this law will apply only in a much more limited form. There are more than sufficient fields surrounding photons, we just need to build scanners sensitive enough to detect fields that weak (of course without amplifying them)
Umm, passing keys over single photons has been shown experimentally.
Single photon detectors are off the shelf items - try a google search.
Reliably emitting a single photon is a big deal to the folks that care about this stuff.
Many people confuse the Heisenberg Uncertainty Principle with quantum entanglement. They're both part of QM, but they aren't the same view of the universe. You could be picky and say that the Uncertainty Principle is an obvious result of basic quantum principles, but it's also the result of some numbers that describe the way our universe is scaled. Anyway, it doesn't say the same thing in the same way.
Quantum cryptography scenarios normally assume that there exists a public channel upon which Alice and Bob can communicate without the information they communicate being corrupted. The quantum channel is only used for sending uncollapsed wave packets from Alice to Bob, which Bob then collapses in a random manner. They then use the public channel to verify that an untampered communication of data occurred. They just rinse and repeat until the shared key is transmitted.
It's one thing to intercept a closed channel and substitute bad data, quite another to jam a public channel (a radio broadcast, for instance, or a voice call). You could always verify identity using a few bits from the good old one time pad :)
As soon as Alice and Bob are able to confer on the public channel, Eve's intervention will be evident, and they'll just try again until they are able to establish an untampered quantum channel and Alice can communicate the shared key to Bob.
...where one can cover for their own blatant stupidity by claiming, "I was just trolling. You believed I thought that? Joke's on you."