Totally Secure Non-Quantum Communications? 235
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."
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 to solve, since none of this has anything to do with the specific problem he's attempting to solve.
(It's also not a cipher, but we'll ignore that slip.)
It's not meant to be. It's meant to secure communications by ensuring an attacker never hears more than one bit of it. It doesn't take a Ph.D. in cryptography to know that if an attacker can only retrieve one bit, they can't decrypt your message from it.
I'll ignore the rest of your comments, since I'm not an electrical engineer, but they don't sound particularly clueful either...
Re:Why must non-cryptographers be so dumb? (Score:3, Interesting)
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.
Thanks! (Score:1, Interesting)
1) He did not understand Quantum Cryptography; While there an interception of the signal is assumed to be possible (although the known schemes rely on a classical unintercepatble side channel, but this is on another sheet), he won't allow for an interception. It is funny that an professor in EE is not aware of the possibility to cut a wire and put in an amplifier. Modern amplifiers are much faster than the tranmittes bandwitdth of the Johnson noise (and they can switch output impedance equally fast, if needed!). All the stupid scheme breaks down then. Because the phase-destroying properties of amplifiers are not measurable clasically.
2) Hey, what if somebody introduces actually two point near the end to intercept the signal. Think about it.
3) Talking about the pointing vector is funny. It is another formulation of energy transfer.
4) Well - all this is only to make a completely worthless patent worth something
Re:How this works and why it will fail (Score:3, Interesting)
I was thinking about the same lines (pun intended), he seems to model the line just as something were one can only measure I/U at one point (i.e. only one 'tee' connector in the line).
He says that it analysis is impossible by looking at the poynting vector (presumably misspelled as pointing vector?!) though, on page 5, just before the start of section 3.2. That is essentially what looking at different points on the line does, isn't it?
The reason for that is still unclear for me, though, even after reading the paragraph repeatedly. He speaks about the net flow of energy, which you and I are not thinking about here....
But he and his group will surely have put some thoughts into that
What else...? Maybe switch the resistors at random intervals? But that'd make it impossible to determine the changes for the other end...
Re:Problems (Score:2, Interesting)
It does have similarity in that it combines the knowledge of what random choices the reciever made along with the resulting line condition, but the end result is the construction of a OTP that is mirrored on both ends. (Literally mirrored, both ends will have an inverse copy of each other, all the bits will be NOT'ed).
It's important to note that the actual payload data is not sent during the initial bout of random bit flipping, but rather the data is conveyed by saying which of the secure (state unknowable to the eavesdropper) bits made up the message and in what order. This data can be sent clear in a public channel. This is where it is very much like a OTP, since it is unbreakable from a brute force standpoint.