Scientists Make Quantum Encryption Breakthrough 156
Madas writes "Scientists working in Cambridge have managed to make quantum encryption completely secure (registration required) by
putting decoy pulses in the key transmission stream. According to the story this paves the way for safe, encrypted high-speed data links. Could this allow completely private transmission of data away from snooping eyes and ears? Or will it mean film studios can stop movies from being copied when traveling on the internet?"
Decoy Pulses are Nothing New... (Score:5, Funny)
Dude! (Score:4, Funny)
Re: (Score:2)
Re: (Score:2, Insightful)
It's kind of creepy...
Re: (Score:2, Funny)
His girlfriend's other boyfriends?
Tag suggestion... (Score:1, Insightful)
Re:Tag suggestion... (Score:5, Insightful)
The tag system is broken, but there's nothing wrong with the implementation. People can't tag correctly. Look below, all real tags.
Re: (Score:2, Funny)
Re: (Score:1)
Re:Tag suggestion... (Score:5, Insightful)
Re: (Score:2)
Re: (Score:2)
Slashdot's moderation was an early pioneer. Wikipedia kicked it to a whole new level. Given the number of trolls Slashdot gets I was sure that Wiki would fail, but the number of people willing to revert graffiti is apparently enough that nearly all of the pages are useful nearly all of the time.
Tag
Re: (Score:2)
it is an intrusion detection breakthorough (Score:2, Informative)
I really wish they'd rename this technology... (Score:2)
They're different things (Score:4, Interesting)
Quantum encryption is, well, basically nothing about using quantum mechanics to _encrypt_, but to send the key (and maybe the data too). The idea is that you send single photons. So basically if someone tapped into the line, you can't split the photon and get only a bit of the signal. Either you get it or the endpoint gets it, but not both. It makes man-in-the-middle attacks a bit harder. In fact, it claims to make it outright impossible.
Since the whole idea here is to elliminate the possibility for a man in the middle, intrusion detection is something valuable. Mind you, if the sending single photons was as un-interceptable as originally claimed, intrusion should be simply not possible, so I'm a bit stumped as to why would they want to detect something impossible. Maybe they know something we don't about how impossible it really is? (E.g., come to think of it, a laser kind of device inserted on the line could multiply that original photon thousands of times, all the clones having the exact same phase, polarisation, whatever.)
It may be pie-in-the-sky, I don't know, but at least it's one of those sane ideas that aren't too impossible to understand even for the layman. The only "quantum" thing about it is that you send individual quanta of light, i.e., photons. Since it's only one and it's indivisible, only one endpoint can get it. All simple and sane, IMHO.
Quantum computing, on the other hand, I don't know... there must be some sane researchers out there who know what they're doing, no doubt. But the media and marketting hype has drowned it all in so much bullshit it could fertilize a few acres, so from the layman (even with a decent grasp of physics and computing) point of view, it's hard to even tell what it would _really_ do, how it would work at all, and how would it be useful at all.
I've even seen such bullshit claims like that it basically holds all possible states at the same time, so it can calculate anything instantly, since the solution state is already one it simultaneously holds. Which is blatantly bull. If it simply holds all possible states at the same time, that's as good as saying that it has no state at all, or you can't measure it. To get an answer out of the computer, you need to get out of it a particular state which represents the result of the calculation. By that logic I could give you a CD with all possible 4 million DWORD (4 byte, 32 bit) values, from -2 million to 2 million, one of which is the result to your problem. There you go, any problem that has a DWORD result already has the result on that CD, so it was "calculated" instantly. Isn't it an impressive feat? I don't even know your problem, but that CD already has the result to it. It's also completely freakin' useless, if you don't know which one of them. That CD as such holds no more actual usable information that that it's a 32 bit number, which you knew in the first place.
Not saying that that's what the actual researchers study, but that's the kind of bogus info that you see from the outside. It's damn hard to tell if it's actually something that might work, or just snake oil to get a clueless VC's money. On par with extracting free energy out of water, the Infinium console, and other such fine con schemes that some people actually dumped millions into.
The only sorta working quantum implementations so far, are basically not even as much quantum computers as hyped, as glorified analog computers. The thing about quantum mechanics is that 99% of it are probabilities.
As some trivial examples, you can't tell for example exactly where an electron is in a potential well (e.g., in a CMOS transistor), or in some cases even if it is still in the potential well or it's out of it already, but you can calculate a probability cloud of, basically, what are the chances of it being in this particular point. Or if you do interference with electrons (think the school physics experiment with shining a light through two thin slots, o
Re: (Score:3, Informative)
The problem w/ QC is having enough entangled qubits to get up to useful capacity..and its an insanely difficult engineering challenge.
http://en.wikipedia.org/wiki/Quantum_computing [wikipedia.org] is a good intro to QC.
While I agree that VC's will hype anything, your post is FUD crossed witha bit of 'get off my lawn, young whippersnappers'; its also clear that you didn't s
Re: (Score:2)
IBM is a big entity. They have a lot of pure science research going on, but they also have more PR bullshitters than Saruman had orcs. Are you sure which department you got your info from? So far a lot of other research PR announcements coming from IBM have been, well, certainly not outright lies, but ommited enough context that a layman would be highly lik
Re: (Score:2)
I've even seen such bullshit claims like that it basically holds all possible states at the same time, so it can calculate anything instantly, since the solution state is already one it simultaneously holds. Which is blatantly bull. If it simply holds all possible states at the same time, that's as good as saying that it has no state at all, or you can't measure it. To get an answer out of the computer, you need to get out of it a particular state which represents the result of the calculation. By that logi
If only anyone invented something like that :) (Score:2)
For starters, a set of qubits can hold a lot of information, basically some analog numbers, but it doesn't automatical
Re: (Score:3, Informative)
Re: (Score:2)
No, it's a perfectly decent objection. A quantum superposition of states is much less than 'hold[ing] all possible states" and to suggest that it is is misleading. For example, given an n-qubit system, you can store no more than n classical bits in it, rather than the 2^n or so that the "all posible states" picture suggests. Similarly we know that we can perform a quantum database search on N items in time sqrt(N) using G
Re: (Score:2)
It so happens that that's perfectly useless in practice. Schroedinger's cat is a very useful mental image for an introduction to quantum mechanics, but for any kind of computing theory the deal is that at some point you have to open the lid and see if the cat is dead or not
Re: (Score:3, Interesting)
Stop piracy? (Score:5, Insightful)
No. Not at all.
Quantum "encryption" foils interception of a data stream. That has nothing to do with copying a file and resending it once it reaches its destination.
Mod parent up - it's easy to steal from servers... (Score:3, Informative)
This is the same reason why many, if not most, "SSL-protected" or "SSH-protected" servers are really sitting ducks: interesting data is still sitting in the clear on the endpoint servers' hard drives. (And don't get me started about "AUTH TLS" email forwarding...)
Re:Mod parent up - it's easy to steal from servers (Score:2)
Ok, what's the weak link here? Is it as bad as plain text or are you just griping about worst case scenarios where space aliens can decrypt our email with their hyper-advanced technology?
Re:Mod parent up - it's easy to steal from servers (Score:4, Interesting)
"AUTH TLS" email forwarding (Score:2)
If you want to get serious about encryption in email,you should probably be checking out SMIME (or at least PGP)...
Re:Stop piracy? (Score:5, Insightful)
Even if you had some special quantum device to allow people to watch something once, only to have its quantum state collapse (or whatever), you could still record the output. With a camcorder, if it came to that.
"Trying to make bits uncopyable is like trying to make water not wet." - Bruce Schneier, cryptography expert
Re: (Score:2)
Yeah, you would think that, wouldn't you. But apparently, the best minds of the entertainment industry still can't grasp that one.
Re: (Score:2)
That's why you use one-time-pad. Send the key first, then, after you know it has been recieived, send the data. If someone snoops, then you know about it, and you don't use the key.
Re: (Score:2)
This 'one time' analogue loop (without tapes and so on in the mix) will still sound FAR better than most of the retarded low-bitrate lossy-compresssion algorithms we are expected to accept.
Re: (Score:2, Informative)
Re: (Score:2)
I'm talking about the MANY sources that are 128Kbs mp3, or even 96Kbps mp3 (stereo music radio too), and also often encoded using an encoder that isn't very good.
Are you really trying to say that download music services (for this is what we're talking about due to the conext of piracy and encryption) provide good quality 192kb/s or 256kb/s downloads ?
You t
Re: (Score:2)
Re: (Score:3, Informative)
Re: (Score:2)
Re: (Score:3, Informative)
And the only thing you need to transfer the signal is apparently an uninterrupted fibre-optic line.
But this
Re: (Score:3, Informative)
Pessimism (Score:2)
That really depends on who you ask. 100 years is definitely a pessimistic claim. That said, I'm fairly pessimistic, too.
Quantum cryptography and man-in-the-middle (Score:1, Informative)
Re: (Score:1)
Re: (Score:2)
Full Text (Score:5, Informative)
Working at Toshiba Research Europe in Cambridge, scientists found that laser diodes used to transmit keys used to encrypt data, known as Quantum Key Distribution (QKD), sometimes transmitted more than one photon at a time. Quantum encryption works by transmitting key data as a stream of single photons.
Should an eavesdropper try to intercept the transmission, monitoring a single photon would change the state of that photon, and this would make both ends of the transmission aware that the data had been eavesdropped. However, the laser diodes can sometimes transmit more than one photon and so a hacker could monitor the second photon, leaving the first photon unchanged and this would not alert anyone that the key transmission had been compromised.
But scientists have now added decoy photons to the key data. When an eavesdropper now tries to monitor extra photons, they will also monitor the decoy photons. Scientists said these decoy photons or "decoy pulses" are weaker on average and so very rarely contain two or more photons.
If an eavesdropper attempts a pulse-splitting attack, they will transmit a lower fraction of these decoy pulses than signal pulses. By monitoring the transmission of the decoy and signal pulses separately this type of intervention can be detected, according to scientists.
By introducing decoy pulses, the researcher found that stronger laser pulses could be used securely, increasing the rate at which keys may be sent. By using this method keys could be transmitted securely over a 25km fibre to an average bit rate of 5.5kbits/sec, a hundred-fold increase on previous efforts.
"Using these new methods for QKD we can distribute many more secret keys per second, while at the same time guaranteeing the unconditional security of each," said Dr Andrew Shields, Quantum Information group leader at Toshiba Research Europe. "This enables QKD to be used for a number of important applications such as encryption of high bandwidth data links."
The researchers also discovered a second method to push bit-rates even higher for QKD. The scientists have created the first semiconductor diode that can be controlled with electrical signal input to emit only single photons at a wavelength compatible with optical fibres. This 'single photon source' method eliminates the problem of multi-photon pulses altogether, claimed the research.
The single photon diode has a structure similar to an ordinary semiconductor light emitting diode (LED), but measures just 45 nm in diameter and 10 nm in height. The dot can hold only a few electrons and so can only ever emit one photon at a time at the selected wavelength. The source operates with only electrical signals, which is essential for practical applications such as QKD. Initial trials with the new device, reported recently in the scientific journal Applied Physics Letters, showed the multi-photon rate from the device to be fives times lower than that of a laser diode of the same intensity.
Slashdot comment #18105678, Concerto No. 2, Op.83 (Score:1, Funny)
Editor, editor... (Score:5, Insightful)
Re: (Score:3)
Several people actually. If you submit an article that gets accepted, you get a link to your page. So you gain by having that link there because it drives some traffic to your site. Slashdot gains because there is now an incentive for people to submit good stories that will get accepted, and I gain amusement by watching people like you freak about nothing.
Too much irony? (Score:2)
What the hell? (Score:3, Insightful)
Really what nerd approves a summary like that?
ahem (Score:3, Informative)
Re:ahem (Score:5, Informative)
Public key encryption is, in practice, used pretty much the same way as well. Public key algorithms are generally used as part of a secure key exchange protocol rather than encrypting a message as directly.
Re: (Score:3, Informative)
The problem with popular public key algorithms is that they are based on the assumption that the opponent doesn't have enough computationnal power in order to break it in a reasonnable amount of time, or he doesn't know a polynomial determinist algorithm to do so.
The big advantage of using quantum key distribution is that it will (ideally) ensure that the cryptographic key you get has not been sniffed, and that you can securely exchange a key which is long enough in order to use a one time pad (which is a
Re: (Score:3, Informative)
"Unconditionally secure" assumes you have a perfectly random generator for your one-time pad. If I can find a way to predict the next number your RNG gave you, I may be able to defeat your one-time pad.
Good random numbers are easy to obtain. There are any number of physical phenomena whose randomness is quantum in origin and therefore unpredictable. Just use one of them in a heavily-shielded room to ensure that none of your data leaks and you're golden.
The hard part of using OTPs isn't generating the pads, it's transmitting and storing them securely. QC addresses secure transmission (though you still have to take care to avoid MITM attacks).
Re: (Score:2)
In your own words, a good random number generator is therefore *NOT* easy to obtain.
Re: (Score:2)
In your own words, a good random number generator is therefore *NOT* easy to obtain.
Why not? Secure rooms aren't that difficult to build. Organizations who have reason to care about high security have lots of them.
Reply to whine... (Score:1)
(Maybe I should have AC'd this one!)
Quantum, not encryption. (Score:2)
It is about _knowing_ that the key was intercepted. If someone eavesdrops it, the receiving end knows it, and can tell the sender "Nope, that one was snaffled, beam me another."
Re: (Score:3, Interesting)
-Monitor the fiber for cuts by keeping it lit at all times. Backhoe accidents will still happen, and then you need to guard the cut and use trusted technicians.
-Have huge fiber ducts and pat
Re: (Score:2, Informative)
Alice sends a stream of photons to Bob with random linear and circular polarisation. Call the string of bits represented by the linear polarisation 'a' - up is 1 and down is 0. The string represented by the circular polarisation we'll c
Re:ahem (Score:4, Interesting)
What the parent suggests is the man-in-the-middle Dave intercepts both all and any communication between Alice and Bob. Alice sends a stream of photons over the quantum line, and Dave intercepts. Afterwards Alice does the public announce to check that bits havn't been intercepted, but Dave intercepts this message also, and this time acts as Bob to verify the photons recieved. Alica and Dave agrees that there isn't an eavesdropper on their line and starts communicating.
So know Alice is communicating with Dave instead of Bob. Dave repeats the same with Bob, but now as the sender. Bob believes that Dave is Alice and they get a link established. Now Dave has one line open to Alice and one line open to Bob and can retransmit what he wants. Nothing of this violates Quantum Theory, because instead of eavesdropping, Dave has created two communication channels.
The only problem Dave has to implement this is that he has to be able to intercept both the quantum channel and the public channel.
Re: (Score:2, Informative)
which is pretty much what was stated.
What one man makes (Score:2)
Point to point (Score:5, Informative)
Re: (Score:3, Insightful)
I dare anyone to cite a single practical benefit over existing zero knowledge key agreement systems.
Re: (Score:2)
It makes your execs feel warm 'n fuzzy.
Re: (Score:1)
finaly! (Score:4, Funny)
Re: (Score:1)
Copying movies (Score:2)
Why is that sentence there? OK, there is a new type of encryption - but how exactly does that relate to capturing movies while the roam free on the internet?
Is there something I'm missing - perhaps a tubes joke...
they are watching (Score:2)
Don't give them any ideas.
I can see the headlines now... (Score:5, Funny)
Re: (Score:2)
The drawbacks others haven't mentioned (Score:5, Informative)
There's also the limit of 5.5 kbps, though that might be improved.
The issue that should have killed this idea ten years ago when Shamir pointed it out is that an attacker who has spliced the fiber can read the polarizer without ever looking at a single one of the transmitted photons.
Send the $#$@! key material by bonded courier in a tamper-evident package if it's that important. If for some reason that's not enough then split (e.g. Blakely-Shamir) the key material into shares, send each separately, and recombine when needed.
Re: (Score:2)
As an OT aside, Beryllium: I love that journal entry about Republicans and refer people to it near-daily. Great work.
Re: (Score:2)
Shamir's attack doesn't affect entanglement QKD. The article appears to be referring to polarization-based QKD, however.
Re:The drawbacks others haven't mentioned (Score:5, Interesting)
If you combine this with the split key concept, so that the difficulty of obtaining a full pad is considerably greater, and perhaps even run each fragment through a public key encryption algorithm to make getting that fragment a near-impossible task, you get damn close to the theoretical level of security offered by an OTP.
A correctly-implemented OTP, in which the pad cannot be derived algorithmically from known quantities, where the pad is not cyclic, and where the pad is used exactly once, cannot be broken at all without physically obtaining the specific part of the pad that is actually used and some computationally-viable method of eliminating any excess. If the pad is rendered unreadable, or the specific information required to make the pad usable simply doesn't exist except at the moment of transmission and then only on the machines involved, then OTP is essentially unbreakable.
The premise of encryption is that nothing can ever be made 100% tamper-proof or uninterceptable, merely very tamper-resistant and very hard to intercept, and so you're far better off making what is obtained unusable. Having something that is supposedly not interceptable is so much snake oil. For a long time, nobody was sure you could undetectably tap optic fiber. What are the vulnerabilities of the endpoints? Is the connection between the "secure" endpoint and the computers at either end exploitable? Are any of the computers involved open to being monitored by TEMPEST or other remote techniques? If the machines are on partially or fully exposed networks, are the machines susceptible to having the transmission intercepted either prior to being secured or after being restored? (Partially exposed can include computers that share USB memory sticks or floppies with unsecure machines. All you need is a carrier for a virus.)
5.5 kbps limit (Score:2)
Isn't the point of this to make it practical to utilize high bandwidth yet unsecured connections to send heavily encrypted data? Even when changing the key very frequently, the secure quantum channel should be more than fast enough.
It's just like satellite TV encryption. The data stream can be received with zero chance of detection anywhere within the satellite's footprint: even less secure than sending data over the internet. By hav
Re: (Score:2)
Nope! (Score:1, Flamebait)
What about.... (Score:3, Interesting)
Re: (Score:1, Insightful)
There is no such thing as unbreakable DRM. Spend your effort comping up with a business model that allows you to benefit from all those millions of people craving to consume your media instead.
Well... (Score:2)
DOS (Score:1, Interesting)
So what if the eavesdropper makes the communication impossible just tainting each and every bit? As they are not safe, they are deemed worthless and the message needs to be re-sent...
This seems to me the problem. You have not built a safe channel, you have built an eavesdropper-aware channel, which is not the same.
Re: (Score:3, Insightful)
"Scientists Make Quantum Encryption Breakthrough' (Score:1)
Very silly article! Not quantum anything (Score:2)
They're intentionally sending MANY photons, to get a stronger signal, to improve the data rate. So they're not using "quantum" anything. They're also adding a bunch of decoy photons, to confuse the evesdroppers.
Nothing at all new here, move on...
Re: (Score:2)
But I still think it's not "quantum" at all if they're upping the photon count.
Grammar Nazi Alert (Score:2)
Scientist Makes ......, in the case of one scientist singular or Scientists Make in the case of several or many scientists plural.
It's impossible to stop piracy (Score:2)
You know why? Because the people you want to protect the content from are the same people you want to sell the content to.
Make it easily available through normal means and piracy will go down.
Military downside? (Score:2)
Breakthrough (Score:2)
im amused (Score:2)
It doesn't stand to benefit ecommerce unless every link in the communication is trusted, and
sounds like obscurity to me (Score:2)
I'll just wait till this actually gets peer reviewed (I'm assuming this as pretty much every "break through" has be broadcasted
Basically, let me know when the article shows up in something like PhysRef. NOT when it's on some newspaper's website.
"Security" is the wrong word (Score:2)
As any geek worth its salt should know, "Security" has three essential and intertwined aspects: Integrity: will the data remain the same and be only changed when and how it should be; Accessibility: will the data stay accessible by those who should have access; and Privacy: will the data stay inaccessible to those who should not have access.
This technique is intended to preserve Privacy, and possibly may help with Integrity; however, quantum cryptography gives no benefits to Accessibility aspects of sec
Registration required (Score:2)
Do you reckon I can break in without registering?
Anyway the first thing you should never do in security is say "this is completely secure".
And how did the summary make the link from "completely private transmission of data" to DRM? It just highlights the fatal problem with DRM - even if we had quantum security, there'd be no way to make bits not copyable.
Re: (Score:2)
Anybody who says that doesn't know what they're talking about. One-time pads, if implemented correctly, are unbreakable encryption. Anybody who claims their security is unbreakable is wrong, because security involves more than just encryption, but it is possible to have the encryption part of it be unbreakable. Still susceptible to
Re: (Score:2)
Since that's the only way to break them, I'd have to agree. :-)
I'd be interested to read any references you can supply indicating that that is the "whole point" of encryption. I have never heard this before. My understanding is the whole point of encryption is to restrict information to those it's intended for.
Re: (Score:2)
Why is that? There are companies that sell random number generation hardware. Are you saying they're flawed or something?
You'd have to kill me if you told me. Feel free to trot that out, but I hope you don't expect me to take your word for it.
Re: (Score:2)
I've never heard this before - do you have any references, or will a google search turn them up?
Doesn't really matter, I'm not going to believe "I know of a counterexample, but I'm not going to tell you" regardless of how good your reason for not telling m