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Totally Secure Non-Quantum Communications?
Posted by
ScuttleMonkey
on Sat Dec 10, 2005 01:32 PM
from the i-wouldn't-use-the-word-totally-yet dept.
from the i-wouldn't-use-the-word-totally-yet dept.
An anonymous reader writes "TEES is reporting that Dr Laszlo Kish, an associate professor at Texas A&M, has proposed a 'classical, not quantum, encryption scheme that relies on classical physical properties -- current and voltage. He said his scheme is absolutely secure, fast, robust, inexpensive and maintenance-free and relies on simultaneous encrypting of information by both the sender and the receiver.' The scheme uses properties similar to Johnson noise along with Kirchoff's Law to provide what he hopes to be an easier method of secure communications. Arxiv also has the full text [PDF Warning] of the paper."
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Simple Comm Technique Beats Quantum Crypto 164 comments
Atario wrote us with a link to a New Scientist article about an innovative new way of encrypting communications. An engineer at Texas A&M may have a way to exploit the thermal properties of a wire to create a secure channel. The result could be an effectively impenetrable way of securing communications, possibly outperforming quantum cryptography keys. "In their device, both the sender Alice and the receiver Bob have an identical pair of resistors, one producing high resistance, the other low resistance. The higher the total resistance on the line, the greater the thermal noise. Both Alice and Bob randomly choose which resistor to use ... Half the time ... they will choose different [resistances], producing an intermediate level of thermal noise, and it is now that a message can be sent. If Bob turns on his high resistor, and records an intermediate level of noise, he instantly knows that Alice has chosen her low resistor, in essence sending a bit of information such as 1 or 0. Kish's cipher does this many times, sending a random series of 1s and 0s that can form the basis of an encryption key, the researchers say."
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A lesson for venture capital (Score:4, Funny)
Kish said that the dogma so far has been that only quantum communication can be absolutely secure and that about $1 billion is spent annually on quantum communication research.
I guess the quantum bubble is about to burst.
Re:A lesson for venture capital (Score:4, Informative)
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Re:A lesson for venture capital (Score:3, Informative)
In Quantum Cryptography, traditional man-in-the-middle attacks are impossible due to Heisenberg's uncertainty principle. If Mallory attempts to intercept the stream of photons, he will inevitably alter them if he uses an incorrect detector. He cannot re-emit the photons to Bob correctly, which will introduce unacceptable levels of error into the communication.
If Alice and Bob are using an entangled photon system, then it is virtually impossible to
Re:A lesson for venture capital (Score:2)
Re:A lesson for venture capital (Score:3, Insightful)
Re:A lesson for venture capital (Score:3, Funny)
If I were paranoid, think I'd rather exchange CDs at a nondescript restaurant in Prague!
Re:A lesson for venture capital (Score:3, Informative)
Yes, but without overlay network. Quantum cryptography works only for directly connected hosts, so it is basically useless except in some very special scenarios. I think the only reason quantum crypto (and that should be properly 'quantum modulation' or the like) as well as quantum computation is so popular today is because it captivates peoples imagination. Since quantum crypto is really just key excahnge, you could allways replace it with pre-comottated random keys in the neighb
Re:A lesson for venture capital (Score:4, Informative)
People no longer understand p2p as "point to point", but rather "peer to peer". Point2Point cannot use significant IP addresses, but Peer2Peer must use them (or something similar).
Which means when Bob and Alice trade IP addresses,
I hope you meant "IP address" in some metaphorical way. There is no way QC can be applied to operate over an internet with real IP address. IP requires routing, and routing means packet-forwarding, but QC depends on an photonic signals that are irreproducible, and thus unroutable.
you ought to be able to have each other's IPs
Do you know the IPs of every mail-order vendor from which you might wish to order?
What you're doing is repeating the usual QC-request to have the initial exchange of recognition data left off of the vulnerability analysis, because it is in fact susceptible to every kind of man-in-the-middle assault.
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Re:A lesson for venture capital (Score:3, Insightful)
It is like speech recognition, VR, kitchen helper robots,
It does not make a lot of sense technologically, but you can get grant money for it easily, because it matches what nonexperts think computing should be able to do for them. Stupid, but very human.
Re:A lesson for venture capital (Score:5, Funny)
Well, it both is and isn't.
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Interesting.... (Score:4, Funny)
Re:Interesting.... (Score:2)
Re:Interesting.... (Score:5, Funny)
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Re:Interesting.... (Score:4, Funny)
But you must admit it does have potential.
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Credibility (Score:4, Insightful)
This is the first sentence from the article. I'm sorry, but I cannot take anything in that article seriously. On another note the guy has an interestingly hungarian sounding name.
Too much hype (Score:4, Insightful)
Haven't we heard this before?
Generally, if something sounds too good to be true, it usually is neither good nor true.
Implementation (Score:5, Insightful)
For example, he claims an eavesdropper could inject current to measure voltage drops, but would be discovered on the first attempt. If the eavesdropped can send a pulse of current that is so small as to not be registered on the endpoint equipment (which say samples the line at 1X sampling rate), but the attacker is injecting and sampling at a rate 100X faster, the attacker's pulse will be so far above the nyquist bandwidth of the endpoints that they will never see it.
I admit I only read the abstract, he may address this later on in the paper.
Voltage drop? (Score:2)
Re:Voltage drop? (Score:2, Insightful)
Re:Voltage drop? (Score:3, Informative)
The is more to a butt set than it being a corded phone with alligator clips. It ha
Re:Implementation (Score:2, Insightful)
Keep in mind that the energy from the attacker's pulse doesn't just go *poof* and disappear. It will be aliased to frequencies within the bandwidth of the endpoint(s) and might still be detected.
How this works and why it will fail (Score:4, Interesting)
What seems to be the flaw in this is that he assumes that the attacker must inject current unidirectionally to determine which resistance is at which end. Perhaps another means exists, courtesy of the speed of light.
Namely if you monitor the voltage at two points along the wire then you can distinguish between a wave proapgating from left to right and right to left. So you can now determine what fraction of the noise is coming from the left and what is coming from the right. Even if the noise level made his hard to do, there's also the moment of the resistor switch to capture. Each time the resistor is changed, even if it were perfectly synchronous, the left side's noise will reach the left tap sooner he the right tap.
This last effect could possibly be masked by injecting large amounts of noise into the system during the switch. (but of course this would also mask any current injection by the attacker as well). But the former effect of the noise signals propagation might still be detectable.
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Re:How this works and why it will fail (Score:3, Interesting)
How sensationalist ... absolutely secure, haha! (Score:2, Insightful)
Oh, the sensationalism!
Re:How sensationalist ... absolutely secure, haha! (Score:2, Insightful)
Pinch of NaCl (Score:2, Insightful)
The only way an eavesdropper can determine which resistance is being used at which end is to inject current into the communication channel and measure the voltage and current changes in different directions. Doing this, though, exposes the eavesdropper, who is discovered with the very first bit of information extracted.
But what if the eavesdropper was present from the very beginning, how will they be
Sounds like Snake Oil... (Score:3, Informative)
In related news, perpetual motion device perfected (Score:2)
There is no such thing as a perpetual motion machine, an honest politician, or perfect encryption. All three exist in theory, but never in reality.
It may be that this new scheme does represent a method of encryptions that is on-par with the best existing methods, or perhaps
Re:In related news, perpetual motion device perfec (Score:3, Informative)
Well, let's see. The perpetual motion machine doesn't exist, in theory, because the laws of thermodynamics and whatnot essentially rule it out. Of course, it may exist in somebody's theory, but their theory would be at odds with actual, working theories that correspond with reality.
You're closer to the mark when it comes to the honest politicians. I think t
quantum recording (Score:2)
How about recording the signal after it has been transmitted through some output at the other end? This bugging would not interfere with the signal being transmitted but would still record the information for transmittal later? If you are transmitting the information through a computer, I think s
Very interesting but what about tolerance? (Score:2, Informative)
Why must non-cryptographers be so dumb? (Score:3, Insightful)
There's so much wrong with this, I don't know where to start.
First, Cryptography is hard. Even professional cryptographers with decades of experience still get it wrong -- often. Considering as this guy has essentially no previous experience (he's an EE professor), it's already near certain that he's dead wrong.
Second, he doesn't provide "absolutely secure" communications. He provides non-interceptable communications. He's totally ignoring authentication, non-repudiation, man-in-the-middle attacks, and half a dozen other very important problems. (It's also not a cipher, but we'll ignore that slip.)
He also assumes (from the abstract) that an eavesdropper can only eavesdrop by injecting current into the wire, which is blatantly false. One could easily tap the magnetic field generated by current in the wire, without drawing very much power from the wire at all.
And to top it all off, he's depending on the precise values of voltage and current, which means this is an analog system. Analog systems are notoriously difficult to build precisely -- which is why we're using digital everywhere.
This is such bad research that I can't wait until Bruce Schneier [schneier.com] get ahold of this.
Re:Why must non-cryptographers be so dumb? (Score:2, Interesting)
It is. On the other hand, since crytography has nothing to do with the problem he's working on, this is an irrelevant observation.
He's totally ignoring authentication, non-repudiation, man-in-the-middle attacks, and half a dozen other very important problems.
Yup. He's also ignoring global warming, terrorism in Israel, and numerous other very real problems that are nevertheless irrelevant to the problem at hand. You appear to have misunderstood what problem he's attempting
I dunno--why are you? (Score:3, Insightful)
He is doing cryptography in the quantum cryptography sense--a secure, non-interceptable channel--not in the algorithmic cryptography sense. He is well-qualified to talk about the kinds of systems he is talking about.
Second, he doesn't provide "absolutely secu
Re:Why must non-cryptographers be so dumb? (Score:3, Interesting)
Someone explain please (Score:2, Insightful)
FTFA: The way the eavesdropper gets discovered is that both the sender and the receiver are continuously measuring the current and comparing the data," Kish said. "If the current values are different at the two sides, that means that the eavesdropper has broken the code of a single bit. Thus the communication has to be terminated immediately."
And it also assumes that measureing equipments themselves are calibera
"Security by Obscurity" (Score:3, Insightful)
Of course, the attacker may be the receiver, in which case she KNOWS the value at one end. And that is the trivial breaking case.
Ratboy.
something to wonder about (Score:3, Informative)
There is also the slight problem of the common clock which must be available at each end. Somehow both sides need to be synchronised which implies either quite expensive atomic clocks or a side channel containing the information. Either limits the practibility of the idea.
Problems (Score:4, Informative)
As I mentioned, this is 100% secure, and any reasonably well-written book on cryptography will confirm that. To be 100% secure, however, the keystream must be as large as the data being encrypted, and must be absolutely random -- any degree of predictability can lead to breakage (e.g. search for "Venona").
The biggest shortcoming of a one-time pad is the key: first you have to generate an absolutely random key, and then you have to distribute that key to the people at both ends of the communication securely. The usual problem is that if you can communicate that key reliably, then you could normally communicate the data reliably just as easily. As such, a one-time pad is typically only useful in fairly limited situations like a spy receiving a DVD-ROM full of key material during a f2f visit, then using the key out in the field. For more typical scenarios it's rarely useful though.
This scheme seems to cure one, but definitely not both of those problems. It's basically a way of using two one-time pads simultaneously, so that the receiver can deduce the sender's key at any point, but what is transmitted over the wire basically depends on both his own key and his partner's key (not exactly an XOR, but a bit like it). If all the attacker does is collect the voltages on the line, I wouldn't be too surprised if this really is secure.
That doesn't mean there aren't any shortcomings though. One obvious problem is that both ends still have to generate absolutely, 100% random keys. Another problem is a man in the middle attack. If the pattern of resistor changes can be predicted, then the attacker only has to find the value once at one end to break all subsequent communications over the channel. Since the scheme doesn't (at least by itself) provide any kind of confirmation of who's on the other end of a line, a man in the middle has a pretty easy time with things.
Another approach would be to tap into the line at two points, preferably widely separated. Since the current only travels over the wire at (about) 2/3rds the speed of light, when one end changes a resistor, the change in voltage/current will be detectable first closer to that end, and some time later at the other end. Two widely separated measurments would allow an attacker to figure out which end changed resistors at any given time. Ultimately, the degree of separation does't even have to be particularly huge -- larger separation just reduces the precision of timing necessary, but even one foot apart gives about a nanosecond.
Absolutely secure communication already exists (Score:3, Informative)
Re:Padlock by Via? (Score:2)
Re:Padlock by Via? (Score:2)
Apart from having used the word "encryption" in the description of both of them, they have about as much to do with each other as a shoe and a condom (both are pieces of "clothing").
Re:Padlock by Via? (Score:4, Funny)
In my case... they both cover a foot
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Re:Nationality (Score:2)
Re:Outdated and irrelevant (Score:5, Insightful)
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Re:Outdated and irrelevant (Score:2)
"They can't stop the signal, Mal!" - Joss Whedon must be part geek.
Re:So this is what I've been hearing on the CB (Score:2)
Re:Would this idea defeat the system? (Score:3, Insightful)
As for "several thousand combinations"... After the first 32 bits of information you have 4,294,967,296 possibilities, so I hope you are a good guesser.
Re:Would this idea defeat the system? (Score:4, Insightful)
Another way to see it: if the signal in your induction pickup were truly undetectable then we could wrap billions of similar induction pickups around the communications wire and generate electricity "too cheap to meter".
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Re:I can break that! (Score:3, Funny)
I read your post. His PhD is solidstate physics makes him more than qualified to talk about this sort of thing. You on the other hand are NOT. You don't even know what cryptography means OR how to spell it. This has nothing to do with cyphers and everything to do with setting up a physically secure