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Holographic Sonar Cryptography
Atomic Snarl writes: "New Scientist.com has this story on how to encrypt a underwater sonar message using multiple sound path timing.
By detecting and adapting for the current variations on underwater sound channels,
the transmitted message can be received intelligibly only at a single point.
This holographic approach suggests a method of web encryption using multiple
hop paths and ping times to create a message which can only be decoded when
received at a specific target node!"
It seems to me that the speed of sonar through water is a physical certainty; that's why we can accurately use it to detect the distance from an object.
Internet traffic is another matter. If I tried to use a ping time to measure the geographic distance to another server, I'd be about as scientific as the Slashdot poll.
Am I wrong, or could internet latency give or take 100 ms or so from a ping, rendering the encrypted message readable by.. no one?
"Beware he who would deny you access to information, for in his heart he deems himself your master."
A well-seasoned network admin friend of mine and I once had a conversation over dinner about an idea I had brewing -- An application that would attempt to guesstimate where you were on earth based on triangulating distances from known servers by means of measuring ping time. A small network database that contained, say, a hundred servers nationwide that constantly maintained a list of ping times to a hundred other machines would provide enough coverage and enough data to allow a single machine to guesstimate where it is on earth based upon simple trig.
The only problem with this idea is that A) Network latency times can change erratically from moment to moment, and B) Some nodes may even drop out of the network due to upgrades or flaming death. Depending upon how fine-grained the mesh is, and depending how accurate you want the guesstimate to be, you could be reasonably certain of at least being able to determine your location within a couple hundred miles.
Not useful for you and I, I know.. But it would be kinda cool if people could buy PCs, set up them straight out of the box, and the box goes out on the mesh and figures out where it is in the U.S., and sets the time accordingly, suggests local IPs, other stuff.
Amazing what you can discuss over a bacon cheeseburger, eh?
Cheers, and yes, PROPAGANDA is still up,
Bowie J. Poag
"This holographic approach suggests a method of web encryption using multiple hop paths and ping times to create a message which can only be decoded when received at a specific target node!"
This implies that all routes are static and no routers ever will go down. It also implies that pingtimes are constant between routers/hosts. Both with are false.
If the IP of all intermediate routers are used in the encryption (which isn't clear) a change of route will make the current 'key' unusable. Further, the ping-time between hosts/routers vary alot as the use of internet vary and will also make this system unusable. A simple DoS-attack will completly destroy any encrypted data in transit which will make it only more insecure.
--
Börnie
Even if you could eliminate the problems with the latency, the asymmetric routing that exists in the internet will kill this technique. This communication technique depends on the forward and the reverse path being identical - something which is not true when asymmetric routing is used.
There is no such thing as luck. Luck is nothing but an absence of bad luck.
will this article on slashdot mean that the FBI will now 'tap' the oceans too??
Fighting for peace is like fucking for virginity
A much more detailed (7 pages) article on time-reversed acoustics appeared in the November 1999 issue of Scientific American.
I pasted the summary below, but here's a link to the summary just to make it official.
Time-Reversed Acoustics
Mathias Fink
Record sound waves, then replay them in reverse from a speaker array, and the waves will naturally travel back to the original sound source as if time had been running backward. That process can be used to destroy kidney stones, locate defects in materials and communicate with submarines.
I thought it was so cool that I wrote a program to simulate the effect. It simulates 1 or more waves emitted by 1 or more sources, and records the waves at 1 or more "microphones". It then treats the "microphones" as "speakers" and plays back the time reversal of the recording. At first the screen is filled with chatoic expanding circles, but after a while the expanding (and fading) circles combine to create a CONTRACTING and STRENGTHENING circle!
I wrote it for my own curiosity, and the code is "dirty". If there's some real intrest here I could dig it out and clean it up a bit.
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.
Theoretically, at least.
In astronomy, the coolest research is in adaptive optics (do a Google search and you will be reading in fascination all day). Here it is in a nutshell, step by step:
1) The earth's atmosphere is turbulent. That turbulence causes the images of stars to dance around in telescopes, making the image all fuzzy. This is what causes the stars to twinkle when you look at them. Avoiding this problem is the big reason why the Hubble Space Telescope gets such amazing photos when it is much smaller than the largest telescopes on the Earth.
2) How to fix this problem without launching telescopes into space? Adaptive optics, of course. If you can flex a telescope mirror into exactly the right shape, you can compensate exactly for the distortion that turbulence introduces into the image, removing the majority of the noise from the signal. Suddenly the image becomes almost perfectly clear and steady, not fuzzy.
3) We know that stars look like points of light, even through the largest telescopes. When we receive a fuzzy image, a very fast computer figures out what shape a mirror would have to be to focus that fuzzy image back into a single point of light. That star is called a reference star. Any interesting objects close to that star are also therefore made clear.
4) Commands are sent to mechanical actuators on the back of a mirror that deform it to the correct shape to focus the reference star. This happens very quickly, so the resulting image is steady and sharp, despite all the turbulence in the atmosphere. Neat trick.
OK, so that's how it works.
You can do the same thing to submarines too, if you know what they sound like. The submarine's sound becomes the "reference star" in this case. When you receive the garbled signal, you might be able to correct it based on the sub's sound. If you apply that correction to the message as well, you might be able to hear the message.
This has a lot of problems, so practically it wouldn't work. For example, the easiest way to defeat the intercept is to change the noise that your sub makes, maybe with a random noisemaker. But that makes your sub less quiet. Also, the person trying to make the intercept would have to be listening to the sub before the message is sent, because once the message is sending, that would make the sub a random noise and you couldn't focus the sound. And, since the turbulence conditions change (I don't know how fast), over time your ability to focus the sound into a message would steadily degrade. The sending submarine would only have to figure out how fast the sea conditions are changing, and only start sending the good parts of the message after you've lost your ability to focus the sound.
If tits were wings it'd be flying around.