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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!"
subject sez all
Exactly, they aimed more at reliability -- even though the codes were lossy and reliability was achieved mainly by coherent en/decoding, because noise is incoherent. However, much of that was dropped in favor of faster and better (in that approach) use of homomorhic processing and other DSP techniques.
.. which essentially defines
wave phenomena ... as the theoretical basis of Holocomm, as stated.
Further, Holocomm's "delocalization" feature can be seen also in SHA-1, where *all* output bits change when one changes a *single* input bit. However, SHA-1 hopelessly mixes and merges all the data (as it is intended to do), while Holocomm allows for reversible and selective delocalization.
Thus, in two contrast points to former pure holographic codes, Holocomm aims at (1) non-lossy reversible (2) selective delocalization -- which also allows interoperation with all known cryptography algorithms (that require exact data for decoding). The reliability feature is also further enhanced by the non-lossy aspect of it. As mentioned, Holocomm can also work in lossy modes, including lossy compression -- which can be quite useful.
Holocomm is the first example of a practical quantum mechanical communication and encoding system that affords privacy and reliability, to a high degree, while also offering compression and selective information delocalization.
As such, it naturally has many parallels in several things that are based on wave functions or on the Schroedinger equation
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."
...which leaves the question...
Does this mean that they need more "big rocks" under the Great Lakes, or can they still use the same "big rock" to use this?
"Eustace? Eustace? Are you there? Are you there?" = John Leeming
Could this be used to secure wireless networking? This would be an ideal way, because it is only understandable at one location. I don't know if it would work well though on Seattle Wireless or Brismesh style 802.11 networks.
David
I think the idea Edelmann is pursuing here has some very interesting implications but also limitations. I wonder how stable the environment on greater distances might be, current, the seabed itself, and other environmental influences. The same goes for the suggested idea of using ping times and number of hop points to encrypt a message. These are highly unstable factors and in order to encrypt the message the environment shall be the same for both sides for the time of the communication flow. But I am also not enough cryptographer to really tell. Maybe others can shed some light on this?
The internet lag times on each leg vary from moment to moment, so there's not the same degree of certainty that the speed of sound in water has. This probably wouldn't work. Plus, we've got asymetric crypto, which works very well, thank you.
Also, in the sonar field, would it be possible to guess at the location of a recipient by catching some of the signals? One wouldn't want to give away the location of your subs, would one?
Note to ACs: I won't mod you up, even if you are being funny or insightful. So take a chance! It's not real life!
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
Every time my phone beeps to alert me that "Voice Pricacy is not active" I wonder who could be listening.
It seems like an approach somewhere between the holographic approach, and the web 'node' approach could be applied to digital/PCS/cell/mobile phones. Does anyone know about research being done into voice privacy on mobile phones?
if you understood the algorithm, you could brute force through all possible points
or if you had intelligence about the destination...
this isn't so special.. a key is a key is a vector (even literally)
You see, even though you are posting "anonymously", it's very easy for CmdrTaco to figure out your IP and correlate it with that of an account...
So, don't be surprised when CmdrTaco mails you and demands an apology.
While underwater encryption is a nifty idea, I would much rather we discuss the US government plans to start using powerful sonar communications that, in test runs, have caused whales to beach with under highly atypical signs of death (the equivalent of bleading ears).
Supposing one intercepted the signal underwater it could still be decrypted. Admittedly this would require formidable computing power since one would have to simulate the geometry of sender and reciever in a continuous medium.
In communications across the net this kind of playing around with different routings and time delays would not be as effective since once intercepted the decoding would be assuming a descreet medium (only so many different pathways). It isn't clear whether the effort put in this kind of scheme would be worth it, ie. it could bne much more effective to refine the encryption algorithm.
One should note that in descreet systems, like electronic locks that open when a transmitting key is waved in front of it, the principle of asynchronous signaling is already in use. These systems use clockless processors to make the recording and decoding of the transmitted signals near impossible.
Any talented writers here?
I'd like to see a witty dialogue made of that.
"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.
kewl, next time i fart in the pool, i'll have to try to encrypt it :)
So let me get this straight, they are suggesting that a submarine can communicate securely with something else in the water ... by being really noisy.
I can see that going down a treat when a sub is trying to keep itself invisible.
will this article on slashdot mean that the FBI will now 'tap' the oceans too??
Fighting for peace is like fucking for virginity
So they've basically reinvented the one time pad, just using the environment as a key...
Multiple routes seems to be pretty hard to come by.
I'm pretty sure huge majority of systems on the net can only send packets to one gateway and don't have any control in the route those packets take.
For years, I've been reading about the idea of data transmission using quantum entangled pairs of particles (possibly photons). The idea (Bell's Hypothesis) being that measurement of a property (eg spin) of a quantum particle will affect the property of another particle (which it has previously interracted with) instantly. That's instantly - not at the speed in light. This has been tested in the lab and proved to be true.
This effect could be used for communication and would imply two things:
1. As stated above, the communication would be instant, regardless of distance.
2. It is impossible to intercept the message with affecting it as any measurement will affect the result.
If it could be made to work, then you would have instant, uninterceptable communications. The problem being how you separate entangled pairs and get them to each end of the line. It's only been tested with distances of about 10 feet so far.
This sig made only from recycled ASCII
If you think in term of a small distributed network with all point to point secure connections established, how can this be utilized to verify the identity of a new participant?
The next great MMORPG.
is ìt a crucial part of the article that i missed, or couldnt *anyone* just listen in on the conversation from whereever they like and distinguish two different sets of sounds? i mean, the sounds wouldnt be exactly like the ones the reciver gets, but wouldnt they still be able to
tell the two waves apart? if they can then this is pretty hopeless
k
-- gunzip-howto.tar.gz
It strikes me that this system is almost an 'obscurity' based encryption which we all know is never a good thing :-)
The technique reminds me of something I read a while back about a 'directional' loudspeaker that could target an individual person in a crowded area (e.g. an airport). It was sort of like 'laser' but using sound waves from different sources which created an interference sound at a certain point.
The exact location of a submarine is of the ultimate concern for its survival during the war time. The holographic approach seems to solve the communication problem.... But, I doubt if that will in fact expose the secret location of a sub.
Decrypting the msg will be hard, but finding out where the constructive/destructive interference zone s are should be much easier... Hopefully, the system won't become a sub location broadcaster.
Although it is a fascinating idea, I seriously doubt you could
use a similar method for encrypting traffic on the present day
Internet.
The biggest show stopper will be the lack of reliable source
routing. Unless you can reliably specify the route the packet
takes (or alternatively, predict the route), the whole schema is
unworkable. IP/4 simply does not support source routing to any
usable degree. IP/6 does IIRC, but even then, I suspect the ping
times will not be consistant enough.
Secondly, a serious change will have to be made to the TCP stacks
as the time interval between the arrival of packets will be an
important factor in this system. Again, I don't see how you can
rely on the transit time given the infrastruture of the Internet.
Don't forget that this infrastructure is what gives the Internet
it's power.
Finally, in the Internet scenario (as opposed to the SONAR
version) this is as about as secure as private key encryption.
Unless my machine is multi-homed, there's likely to be at least
one router that sees every packet my machine sees. This is
fundamentally different to the SONAR version, where you have to
be a precise physical location to be be able to "hear" the
transmission.
Cute idea, but not feasible.
That's what you think.
Try:
http://sarcasta.net/graphics/cleavage.JPG
or even
http://sarcasta.net/graphics/
for all the graphics on that shitty website.
I wonder who's going to be the first brainiac (sorry, excessive VC funded mulch) to try and build some form of network using sound and water as the carrier..
Imagine it in 5 years.. Worldcom advertising "dark water" - buy your unused water now for $$$$, expect high latency!
I suppose you've got a lot of bandwidth (wetwidth?)
"Never let the truth get in the way of a good story..."
In effect the sea floor and positions of sender and reciever are acting as a secret key. They 'encrypt' the messages and you can only decrypt if you know the secret key in enough detail - i.e. you are the reciever, and the working with the sender. However the snooper in *theory* could decode the signal if he knew enough about the sender/reciever/sea bed, and could do some farily complex maths. How complex the maths is says if it will work in practice. But given that computer can model huricanes, I would guess that modeling the sea bed is plauible.
In the virtual world though all bets are off. The terrain is very mappable, and fairly simple. So if the problems of varing ping times can be worked out the encryption is very easily broken.
I wonder if the sea bed version stops working if the tide changes.
DWR is Ajax for Java
While the system that governs this type of communication may not be as chaotic as say the weather, it definitely should have sensitive dependency on initial conditions.
Large amounts of packet loss would occur anytime a fish swims through the line of sight. My question is how sensitive is it to such things. My guess is that a minnow could render a message totally useless. I imagine that is what has kept the Navy from adopting such technology.
int func(int a);
func((b += 3, b));
Whales - the vermin of the seas. I say we should whale the blubbery buffoons.
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.
The same has been done for years in military radio communications.
Use two or more antennas at the transmitter applying phase and time shifts to the signals in the appropriate way and, taking into account the different paths the waves can take, you will have a signal that is combined to produce something useful in the desired spot; in all the other places it will look like noise.
The difference between the water and the Internet is that it's possible to be at different places at the same time, and over a peroid of time on the Internet to intercept trafic.
Darthtuttle
Thought Architect
Hoobajoob.
Quantum, this, applications of that, blah, blah blah. Some people use the big words just to make themselves sound interesting, if not smarter.
I really don't see how you can make the leap from submarine sonar pings to internet communication. You see, the pings are actually quite different, and have no relation that would make one draw this parallel. Barring some of that funky quantum-mojo you're throwing around.
<NITPICK>
Due to the nature of bits (being 0 or 1), changing a bit means flipping them from 0 to 1 of vice versa. Changing *all* bits, would mean flipping them all, i.e. a XOR operation.
Changing a single input bit will change *some* output bits, not all of them. Would be a pretty useless hash algorithm
</NITPICK>
Okay... I'll do the stupid things first, then you shy people follow.
[Zappa]
"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 suggests no such thing, and the post should be updated to reflect this. The way a sonar wave travels through water is so fundamentally different from the way packets move through the net that the comparison is in fact quite absurd. Indeed, the IP protocol in no way supports the kind of controlled packet delivery the poster is assuming.
Guns don't kill people; Physics kills people! - John Lithgow as Dick Solomon on Third Rock From The Sun
This is a common error to think the immediate, non-local interaction between entangled pairs leads to 0-delay communication. This is FALSE.
The measurement of one particle affects immediately the other, true, but in an impredictable manner; so you cannot "force" the other side to be a 1 or a 0; However, if you measure 0, then you are assured the other side measure 0 too (to put it simply).
All of this is not very interesting at first sight, except there are ways to know if someone else measured the passing photons (there are visible perturbations if you are not the 1st one to do a measurement, I don't remind the details). So the real advantage of communicating with entangled pairs of particles is that you can exchange Random one-time pads with the assurance that no-one can intercept it (if they do, you will know and will restart).
So, NO this doesn't give instant communication; But YES you have completely secure communications.
precisely that arrogance that gets you targeted by the terrorists you talk about.
precisely that ignorance that gets us extinct as the climate/ecosytem around us undergoes to rapid a change for us to cope with - but that as you say is evolution , stupid americans die out.
Since I wrote the original, I did a bit of digging and found this (scroll down a bit for a really flash diagram). By affecting the measured polarisation on one end, they are, instantly, affecting the measured polarisation on the other.
Yes, you are correct that the reason it can't be intercepted is that because it would break the message. And, of course, it's totally impractical. Interesting though - and, as a lot of Quantam Physics things are - totally counter-intuitive.
This sig made only from recycled ASCII
Since when does the Internet considered a particle wave system? 'Holographic packets' sounds more like an invention of Steve Gibson than a method with sound scientific and technical backing...
"I'll just chip in a bit for RedHat: I actually have that installed on my university machine." - Linus, '95
... wouldn't I have to get a waterproof computer case to do this?
Don't confuse waves and particles.
This holographic sonar communications system relies on the interference patterns of pressure waves in water (sound). Internet packets do not behave like waves, they behave like particles. There is no interference between them, nor are multiple packets ever combined into one packet.
Quantum effects allow the merging of particle and wave features, but we don't have that sort of technology in place in the internet at this time.
(Though such things ARE being researched.)
~ Chris
1. use an with vowels
1.a. except where the vowel makes a 'you' sound
k, thx
The point of the discovery is that you can send a message, possibly without revealing your exact location. This is not cryptography. There is probably not a lot of (public) research on this subject - it may be very possible to locate a ship regardless. If it is hard to locate a sender this way, the interesting thing seems to be the distance over which this works.
Even if distances don't go much beyond 10 kilometers, you can still create a buouy that a sub launches, and uses as a message relay. Or launch a few while enroute and leave a relay network behind.
Now, if and when this becomes a real world application *nobody* will be sending uncompressed, non-encrypted information over the link. The regular public and symmetric cryptography has a very calculatable 'risk' of decryption in it.
Btw, Like so many others said: the Internet idea is totally bonkers. That won't work.
What makes this a viable option for underwater encryption, is that nobody can sample a big area of ocean entirely to be able to reconstruct the "holographic signal".
But in the internet, it just only obscures your data. Anyone can read it provided it has backdoors in routers in every path you are using. Yeah, it's harder than monitoring a single router, but still possible, so this approach wouldn't give Real Security[tm]
Yeah, but wouldn't the transmit time of sound through water be a lot more constant than that of packets through different internet paths?
I don't think so. Sound travelling through water conforms to well-understood, consistant physical laws. You can accurately predict how long it will take a sound wave to reach a given destination. However, packet transmission time varies unpredictably based on current load, which changes from millisecond to millisecond. With sonar, if a stationary source pings a stationary target, the ping time will remain constant. With TCP/IP, pinging the same address will give highly variable ping times. Since it appears that this technique is highly dependent on timing, an analogous technique isn't possible on a TCP/IP network.
Why is it that the proponents of "one nation under God" are so eager to get rid of "liberty and justice for all"?
They say the problem with normal transmissions is that they go in all directions. This means they're also bouncing off of lots of surfaces and echoing back at different times, which is why the sonar ping works.
However, to play sounds back in reverse as claimed in the article, you'd need to be able to send each piece of the signal directionally, towards the area it came from. If you're broadcasting each piece in all directions, then you're still going to get weird echos off of everything else, and thus end up with weird interference. For the first piece of the transmission this might be OK (since you assume non echo'd transmission will arrive first). But then the echos of prior transmissions will interfere with the actual signal in the parts of the transmission that take longer to arrive. Maybe you could try to subtract these out afterwards? But I suspect its not that simple.
of course this wouldn't be a problem if they could send each piece of the signal directionally, but then if they could do that they wouldn't need this in the first place...
am i missing something?
You can't emulate wave interference on the net (soon to be .NET). With sound or light you can use wave interference to either cancel or amplify a wave form depending on the frequency, distance, and position. The sonar technology is nothing new. The same approach has already been applied to Light, and the NSA has already investigated using this technology for secure satilite transmissions, and the DoD is rumored to be using this technology for secure land-line connections.
However, You can not use wave interference on the net because the information is received as a digital signal. The communication devices have no control over the way the data is encoded on a fiber or copper connection, so its impossible to implement this technology for net traffic. At best if you have control access at both end and you create custom hardware between two points you could use this to encode traffic.
This article does not suggest a way to secure computer networks in the least... I'll read it again twice, but I doubt I'll find the missing paragraph that someone must have read...
Water more or less cooperates and is predictable in terms of transmitting information (in this case sound); a large heterogeneous network is anything but predictable.
AC's cheerfully ignored
Sounds like Bill B's idea re anti-chirping (http://www.amasci.com/hoax.html)
When a large rock is flung into a pond, the waves spread into a series of ripples of descending wavelength, as if the water has "Fourier Transformed" the splash signal. It has! The water surface is not a linear medium, therefore any signal becomes "chirped" in a similar way to the "whistlers" produced in ELF radio sets by distant lightning pulses. If an "antichirp" series of ripples could be made on the water's surface (a temporally-reversed version of the ripples from a big splash,) then as the ripples moved, they would slowly compress together and finally create a little explosion of spray.
Ripples also take the form of an expanding circle. Rather than just reversing the "chirp", we could also reverse their direction. If water ripples could be created as inwards-curving rings, so that they focussed themselves to a point, so much the better.
Therefore build a bicycle-powered wave generator which can be placed at the shore of a pond. It would slowly vibrate a long, curved wall which floats half-immersed in the water. When aimed at a distant unwary duck, a series of ripples is created. The duck sees the distant ripples approaching, and contracting, and concentrating, then... DOOOSH! WAAAK-Aaak quaaak quackquack...
Or build the device onto a large fountain pool. Design the wave-generator to produce several superimposed "antichirp" patterns per revolution of the flywheel. Then, if you pedal at the right speed, a mysterious zone of violent splashing would appear out in the middle of the pool.
Suppose the wave-generator was adjusted to produce a *line* of splashing, and every so often the antichirp waves would contract and produce a long burst of "chop". This line might act to reflect other water waves, especially if the event was repeating at the same frequency as the waves. Perhaps we could trap a standing wave between the shore and a nonlinear barrier made from "chop." Design the wave generator to temporarily create a square *hole* in the water. Make a really big one, so small 3rd-world countries can tickle the ocean for awhile and have it swallow approaching aircraft carriers.
Soliton waves can exist on the surface of water. The "tidal bore" is one such soliton wave. Perhaps a soliton can be assembled from many smaller waves. If so, then a bicycle-powered wave generator could create the smaller waves which contract together, then sum nonlinearly to build a travelling soliton. Very cool museum exhibit!
- A submarine is generally moving, thus sending a message recieveable at 'only one point' is problematical
- If the range is significant, there is a good probability that the sound conditions will change significantly during the combined travel times of the reference pulse(s) and the data pulses.
- Last but by no means least, for this to work over strategically useful distances, the boat is going to have a transmit a fairly powerful reference pulse, which will be detectable by those who the sender would rather not know they are there at all.
In the near term, this maybe useful tactically, but not over strategic distances.Derek L.
USN Submarine Service 1981-1991
High atmosphere ionization trails from micrometeors (of which there are a surprisingly large number every hour) alter the transmission properties of the atmosphere. Given two stations, you do some geometry, and then wait around for a suitable ionization event. When such an event occurs, transmissions will be symmetrically reflected between the two stations as long as the ionization trail has not dispersed too much.
This fact is exploited by broadcasting a pseudo-random (like a DS/SS chip) signal from a master station. When transmission sites that know the chip happen to pick up an ion-trail reflection of the master signal, then there exists for a short time a symmetric path back to the master, during which buffered data can be burst transmitted. If the trail lasts long enough, bi-directional communications may be possible. The system as a whole exhibits classic spread spectrum properties, including low probability of intercept, resistance to interference, and channel sharing.
Meteor burst communication is, however, very low bandwidth, but thats OK - most people using LPI communications aren't exactly streaming MP3s; you can get some pretty good milage with a few dozen bytes of text.
I don't know anything about the power requirements here... anybody have any usefull info, or corrections to my description? Its been a while since I've looked at this stuff.
Their logic seems similar to that of "whisper" chambers, but they break one of the assumptions when they start sending a steady stream of phase encoded ones and zeros. Now instead of having to reconstruct a complex wave form, all an eavesdropper has to do is:
1) Listen for pink-noise with a strong 1kHz component.
2) Play with the (recorded) signal a bit (e.g. adding 1us delayed copies to the original) until you can decompose it into two types of 1us segments--call them A & B.
3) Now you have a stream of As and Bs, and two possibilities; either A=0 and B=1, or visa versa. Test both.
-- MarkusQ
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.
The sonar xscreensaver rocks. It plots hosts on the sonar screen based on ping time.
man sonar:
The sonar program displays a sonar scope on the computer's screen. This scope
polls a sensor as the sweep goes around the scope and displays what it finds as
bogies on the screen. The program is designed to support different modes repre-
senting different types of sensors. Currently the only implemented sensors are a
simulator, and a network ping function that pings hosts and plots the results on
the scope.
The snag is, the only way for them to know that we did it is for us to tell them by some other means. This system can't be used to transmit any information since there's absolutely no way for them to know that the polarization entanglement has colapsed without either 1) measuring it first (which would make them the sender) or 2) getting a regular old non-quantum message from the sender.
So unlike Ma Bell and church Bell's, etc. J. S. Bell doesn't help you get your message through.
-- MarkusQ
It is called NTP and GPS.
Am I missing something, or would this method be completely useless if the submarine is moving in the slightest bit? How do you get a submarine to be motionless? There's going to be currents and such moving it. Won't nearby ships moving throw it off as well?
That's some mighty fine technobabble you've assembled there. If you're not already there, I strongly recommend heading out west and becoming a Hollywood script writer. They need people like you, to make the characters seem smart without actually saying anything.
Seriously though, I should point out that in a hydrological holographic communications medium, the thermal dynamism will, while not affecting the message in, a, lossy way, will cause changes in the order, that, the binary components might be received. It is of course trivial to correct for this, current use of super string theory provides an elegant method for accounting for said brownian reverberations in the stream, but it's still important to XOR the bits into a checksum before sending, just to make sure you understand.
"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!"
There is no analogy between the interference patterns in the water and the internet. The patterns interfere with each other because they are waves. (Recall Physics 1). On the internet, two signals sent down two different paths will (hopefully) not interfere with and distort each other. It is true that if you cut a letter in two, and send it in two different envelopes, someone who intercepts only one will not be able to read the entire message.
This works underwater because the sounds are designed so that their interference is only meaningful at one point in the water and that intercepting the interference pattern elsewhere is always meaningless. I suspect that, if the interference pattern were read at multiple locations, the message could be interperated.
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!"
Two problems with this statement--
#1: anyone listening at the source ISP (Like carnivore?) would get everything, and
#2: The paths would tend to converge, you could TRY to use different routes, but they'd all converge on one of the cross-country links more likely than not.
Sample stated, "The system can transmit data at 1 kilohertz." The unit kilohertz is a measure of frequency, not rate or velocity. What you want is a measure of the scheme in kilobytes (KB). That, is left as an exercise those wanting a (Score:5, Insightful).
Too big to fail? Does that make me to small to succeed?
My backup reasoning is thus; The sounds are intended to carry very long distances without degradation in order to be properly assemblable at the other end. This means that inconsistencies between the various audio streams should make themselves clear and differentiate the various frequencies. If they are layered on top of one another sufficiently, they will interfere with one another, so basically, the longer you're transmitting, the easier it should be to decode your message without being in the right place, because you have to avoid your signals stepping on one another.
Also, it'll make you tragically easy to locate. If they can blow you up, they almost don't need to know what you're saying. Silence being golden and all of that.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
...Especially considering the theory that dolphins and other cetaceans may communicate by means of sonic holography.
Could make things interesting if, say, a blue whale misinterprets part of the transmitted message from a sub as an invitation to mate. Let's see the boat's skipper explain THAT one to Pearl Harbor! (or wherever).
Bruce Lane, KC7GR,
Blue Feather Technologies
The main advantage of time reversal techniques is their robustness : they are quite insensitive to modification in the propagation medium or at its boundaries.
The reason of this robustness is that time reversal provide basically a compensation for each propagation path, and thus final quslity does not depend on a specific path.
Furthermore, when the medium is reflective, and propagation chaotic, more paths exist between two points, and time reversal becomes more robust to small variations ( such as fish, waves, etc...)
Experiments made ny SCRIPPS in Italy were conducted for periods of several days, showing this robustness over time
If one reads the article carefully, one would discover that this "encryption" technique makes use of the wave nature of sound to both obscure the data in transit, and reconstruct it at the final destination.
There is no analogy for web traffic which travels over IP which is sent as discrete packets of bytes. They resulting packets cannot be made to interfere with each other at the destination to produce plaintext, nor do they interfere and reflect and become distorted in transit!
The closest analogy would be to split a message into many small parts and send them along different paths in the hopes that no one could catch them all in transit, but then timing isn't really an issue at all as others have suggested. Also, anyone bugging your connection to the internet (your ISP for instance) could still catch all the packets, ditto for the source. Some have suggested splitting keys and sending some parts by snail-mail, others by FedEx, others by e-mail to different accounts which you read on different machines, and that is really a form of security through obscurity, not encryption, whereas the sonar technique is more like encryption in that even if an adversary knew that information was being send and knew from where, they could't recover the plaintext unless they were at the target location.
Perhaps quantum cryptography is a better analogy to what's going on, but it's not a perfect one either as there are fundamental differences between accoustical waves and quantum wavepackets.
It's a phased array, and they have solved the problem of unpredictable (but not rapidly varying!) propogation velocity, an interesting signal processing challenge. Like all phased arrays, this works on the principle of constructive interference. Two packets arriving at the same time cannot reinforce each other.
From the short description given, it would seem that the system can only reply to an incoming signal, because that signal contains information about propogation velocities. There seems to be no way to initiate communication if the sub doesn't transmit first, i.e. the system can't predict propogation velocity, only measure it.
As far as communication goes, reverse sonar holography seems like it could establish a reliable line of communication, as it uses interference to focus the sound waves at one particular location instead of diffuse them.
However the security of the communication, as others have pointed out, is probably suspect.
At first read, I thought that it would take a considerable amount of computing power to decode this holographic communication. At any point other than the intended target, the recording will be diffused, diluted, and garbled. Increase the number recorder/speakers and increase the broadcast rate, piling more and more garbled sound together and it will become harder and harder to decode.
But what about this attack: If I can sound a ping at the right time so that you record it in your recordings (along with your recording of the honest ping from your base station), when you play back your reverse holographic transmission, I'll get a carbon copy of it delivered right to my doorstep! If I can make my ping frequency match that of your base station, you won't even it got in there.
Looks like you'd better encrypt your 1s and 0s before you send them; you might not know exactly who your data is sent to!
It's been done. It is called geotrace, it's webpage is http://geotrace.sourceforge.net. It is currently only at version 0.0.4, but it works decently anyway. I just performed a trace from me to www.yahoo.com, which you can look at here.
Best Slashdot comment ever
This hits me as a fundamentally new twist on public/private key encryption. I send you my public key (a ping) which you then use to encode a message back to me. Doesn't matter if someone hijacks the ping, because the ping will "appear" differently to them. They can still transmit to me, but they can't decrypt any other message sent from ANY other position, even if they record it and then move into the original transmitting position later. It's almost like a dynamic public key. Very cool.
Sorry, but I think you might have a fundamental misunderstanding here. The time-reversed (acoustic/electromagnetic/arbitrary-wave-equation system) phenomena that this technique is seeking to exploit have very little to do with chaos and nonlinear dynamics. They have far, far, more to do with interference in propagating waves. Think of the wave interference tank in your high school physics class. Randomly place a bunch of rocks into the tank; these are the scatterers. Drop a penny into some arbitrary spot. See the pretty interference patterns (at least in your mind's eye) as the waves spread out? Now consider that arbitrary (perfectly linear) solutions to the wave equation are insensitive to "the arrow of time". (In other words, if you can construct things so that time "runs backwards", then these too are perfectly linear solutions to the wave equation.)
Now, how do you make time "run backwards" you ask? Glad you asked! ;-) Well, this class of techniques cheats a little bit. They simply record a signal due to some source at multiple locations (kind of like an array of seismometers). Once the signal has been recorded, all the transceivers (in pricipal at least) play the signal backwards, but synchronously. Voila! You've created a wavefield that is approximately the time-reversal of the original wavefield (at least in a Huygen's principal sense; i.e. you are unlikely to have complete spatial coverage with your transceivers). This wavefield will converge back to the site of the original penny drop. It will not be perfectly focused (remember, the field is an approximation), but will still do a fairly decent job.
Slightly perturbing the positions of your transceivers (i.e. much less than a wavelength) will not affect the quality of the approximation too much. The quality suffers more if the playback trasceivers are not time-synchronous (and hence are out-of-phase with each other), since then the coalescing wavefield does not constructively interfere. A time varying medium of propagation (such as an atmosphere causing stars to twinkle) poses its own challenges.
Within the confines of the validity of a linear wave-equation phenomenon, and a static medium of propagation, there is NO CHAOS in this system (no nonlinearities, no insets and outsets of fixed points in phase space, etc. etc.). The extreme sensitivity in terms of position of the receiver that you allude to in your post is simply a phase-rolling thing. It is perfectly linear, and the bread-and-butter of lots of people who do practical things with waves (e.g. acousticians, seismologists, radio engineers, add-someone-who-studies-your-favorite-kind-of-wave -phenomenon here).
Hope this clarifies things somewhat, but feel free to flame away if you like. This is after all slashdot, and I would kinda fell left out if I didn't get flamed for a posting.
Euh, ahem, the oceans were wired for sound years ago already. Not joking. Really.
Hydrophones were dotted around to be able to track subs, think it was somewhat declassified a few years ago (gave some new insights in whale behaviour, migration paths etc. then).
Holocomm may have aimed at more reliability, but Spootnik aimed at more Usenet plagiarism.
Please help moderate him to -1.
How much karma should Spootnik lose due to Usenet article theft? I will let you calculate it.