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Optical Cellphones 213

Posted by timothy from the you-can't-hear-me dept.
foondog writes "Here is a story over at News.com about optical cellphones. It seems that the Department of Defense has given a grant to the University of California to develop optical cellphones that are faster and more secure. This sounds a little strange to me since you would need a line of site with no obstacles in the way to use this. The article doesn't explain how this might work."
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Optical Cellphones More

Optical Cellphones

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  • Just plug in to the nearest optical call center an drag the cable around.. duh!

    TM

  • LOS (Score:5, Informative)

    by Wyatt Earp ( 1029 ) on Wednesday November 27, 2002 @03:33PM (#4769513)
    "It seams that the Department of Defense has given a grant to the University of California to develop optical cellphones that are faster and more secure. This sounds a little strange to me since you would need a line of site with no obsticals in the way to use this. The article doesn't explain how this might work."

    What about from a soldier/spy/diplomat straight to a comm sat?

    It's easier to get line of sight to orbit.

    • Uh... signal strength requirements?

      • With current tech? (Score:3, Insightful)

        by mmol_6453 ( 231450 )
        If it proves to be a gov't-use-only technology, why worry about it?

        Instead of looking for specific levels of brightness, look for the delta of those levels. Or even delta^2.

        Given that current satellites are able to read print the size of license plates, and we have a lot of computing power available these days, I would imagine that software could track a single point signal source and ignore others.

        This is a supreme advantage of optical over other methods. We have CCDs that can see visible light and infrared, but no hi-rez CCD that can "picture" radio sources.

        Jamming is only useful if all your signals come in over the same antenna. It's much, much less effective if you can easily distinguish the locations of multiple sources, then authenticate against the source you want to communicate with.

        Granted, this means cell-to-satellite is easy. Not satellite-to-cell.
        • Given that current satellites are able to read print the size of license plates

          I think that's an urban myth [everything2.com]. You would need to broadcast on frequencies that are distinct from any ambient emitters and reflectors which probably rules out anything between IR and UV. Even then the satellite would only see you as a point source. And then, there are no real advantages over radio.
          • Have you looked at current publicly available satellite photos? Even the resolution those supply would be sufficient for point-source tracking.

            Tracking the point-source is probably the cheapest, most effective method available to distinguish between an attempt at jamming and an actual source of signal.

            This is ideal for optical frequencies because you can order the technology off-the-shelf.

            It's even suitable inside buildings because you need only an optical sensor for every open area you want to receive in. I was going to do something like this for my laptop's IR port, at home.

    • Re:LOS (Score:2, Insightful)

      by jaywhy ( 567133 )
      The soldiers/spy/diplomat would have the same problem we had in the gulf war with laser guided bombs. A little sand storm, clouds, rain, anything other then nice weather your screwed. Not to mention, how would these things would work in buildings?

      Wouldn't a better solution be cellphones which support heavy encryption?

      Jason Yates

      • Re:LOS (Score:3, Interesting)

        by mmol_6453 ( 231450 )
        Wouldn't a better solution be cellphones which support heavy encryption?

        No, because at some point or another, the encryption will be cracked, and there may be recordings of the signal, which can be decoded later.

        Unless, of course, you use a one-time-pad system. (But then you have to worry about the entropy level of your key)

        • Re:LOS (Score:2, Informative)

          by martyn s ( 444964 )
          I thought the problem with one-time-pad systems were actually DISTRIBUTING your key. Whatever you mean by "the entropy level of your key," it seems insignificant if people can just intercept your key easily.
  • It doesn't really say anything about how the optical cell phones would work inside a building. I'd be very curious to know how they plan on overcoming this obstacle. Of course, this is just a grant to study it. It may never come to *see the light of day*

  • Can you see me now? (Score:5, Funny)

    by Anonymous Coward on Wednesday November 27, 2002 @03:33PM (#4769518)
    (sorry... had to be said)

  • actually, no. (Score:3, Insightful)

    by User 956 ( 568564 ) on Wednesday November 27, 2002 @03:33PM (#4769522) Homepage
    This sounds a little strange to me since you would need a line of site with no obsticals in the way to use this.

    X-rays are light energy, and they don't seem to have a problem passing through.. well.. you, among other things.

    • Re:actually, no. (Score:5, Informative)

      by spike hay ( 534165 ) <blu_ice AT violate DOT me DOT uk> on Wednesday November 27, 2002 @03:41PM (#4769587) Homepage

      X-rays are light energy, and they don't seem to have a problem passing through.. well.. you, among other things.

      Um, xrays, gamma rays, optical light, radio waves, and everything else is electromagnetic radiation. The penetration ability changes with different wavelengths. Low frequency, long wavelength radio waves penetrate through objects very easily, this is why 2.4 ghz 802.11b goes through walls better than 5 ghz 802.11a.

      Higher frequence microwaves, infrared, optical, and UV em radiation is basically line of sight. Ultra high frequency, high energy, sub microscopic wavelength xrays and expecially gamma rays can penetrate most materials due to their high energy.

  • Optical cell phones??? (Score:3, Insightful)

    by IdleTime ( 561841 ) on Wednesday November 27, 2002 @03:34PM (#4769524) Journal
    Intersting idea, but is it really possible to have a laser based cell phone? I guess a laser would have to be used.

    Besides the technical problems, I really don't see much use for it. I'm happy as long as I can talk on my cell phone and I don't need: games, internet, messaging, carwash, deodorant, floss, toothpicks, swiss army knife, lunch, soft drink incorporated into my cell-phone.

    I'm not that important, neither is the rest of the Slashdot crowd :)
    • Besides the technical problems, I really don't see much use for it.


      Well I guess they just aught to scrap the whole program, then.


      I don't suppose a communication device not subject to the same sorts of interference, jamming, monitoring, and detection as your standard RF transmission would have a whole lot of military application, now, would it?


      You're a visionary, dude.

      • Easy enough to jam - just large random bursts of energy on the same (or nearby) frequencies to overload the receiver. Don't even have to be pointed directly at the receiver. This is the same technique fighters use to jam IR-based sensors on missiles riding their 6 (6 o'clock position == rear). Sort of like how you can't see for a few secs after someone pops a flashbulb in your face.

        Also, some animals can detect light pulses going through shielded optical cables (sharks, for example, just love chewing on underwater fiber-optical cables).

        Because of quantum effects, strange action at a distance, etc., there is no such thing as an event that is not detectable.

        • How to keep your cell phone from being jammed? Bathe it in grape jelly, instead...
          • Spaceballs:

            Corporal Asshole: We're being ... jammed, sir.

            Dark Helmet: It's raspberry jam. Only one person would have the nerve to give me the raspberry - Lone Star!

    • The East German secret service used this (Score:5, Interesting)

      by uradu ( 10768 ) on Wednesday November 27, 2002 @03:48PM (#4769649)
      Not an actual cell phone, but a point-to-point intercom involving binoculars and infrared transmissions. The voice was converted to (analog) IR light and transmitted through optics that created a very narrow beam. At the other end, the IR receiver was mounted in the eye piece of the binoculars and converted the light back to sound. The two devices had to be aimed very accurately at each other. That way a spy in the west could communicate with his pimp in the east across the border with very low probability of interception. They actually had this on the History Channel a few years back.
    • It would be pretty untappable. You'd notice inmediately iF it's tapped. And it can't be jammed electronically, only blocked.

      These are my guesses without looking at the article (ah, that bad habit).
      • Oh, it was X-Rays... changes everything. You can't get away with not reading the articles, it's a fact :).
      • It would be pretty untappable. You'd notice inmediately iF it's tapped.

        You could "easily" tap it by simply inserting your device into the line of sight and then retransmitting. While the receiver would "see" a momentary disruption in transmission, how would it distinguish between someone tapping and say a bird flying through it's path?

        And it can't be jammed electronically, only blocked.

        If you had close to the same LOS as the sender, you could beam a signal to either interfere with the sender or to simply confuse the receiver, though true doing something radio based would not work.
        • You could "easily" tap it by simply inserting your device into the line of sight and then retransmitting.

          Yes, but wouldn't I notice that? The tapping device would have to be invisible to me and to the other end. I mean, i'd set up a line monitoring (a digitally monitored telescope that scans the LOS).

          I'm just thinking about it.
  • Well, see, when your eye starts ringing...

    *i know, i'm just asking for it* ;)
  • This sounds a little strange to me since you would need a line of site with no obsticals in the way to use this.

    Desert. You can only use them in a desert.

  • Using a laser? (Score:5, Funny)

    by bunyip ( 17018 ) on Wednesday November 27, 2002 @03:35PM (#4769535)
    Need line of sight. DoD likes lasers. Big lasers, with lots of power. Could be dangerous.

    I wouldn't want to hold one of these up to the side of my head and start talking, it might make it's own line of sight to the nearest tower.

    Ouch!

    • Re:Using a laser? (Score:4, Interesting)

      by spike hay ( 534165 ) <blu_ice AT violate DOT me DOT uk> on Wednesday November 27, 2002 @03:46PM (#4769635) Homepage
      Lasers are out of the question for this. Lasers produce a very narrow collumnated beam. No good for cellphones. Probably something more along the line of bright LEDs would be better.

      Big lasers, with lots of power. Could be dangerous.

      It wouldn't need to be high power at all. Hobbyists have been experimenting with optical wireless communications for several years. It's not dangerous. Although the hobbyists use fixed points with either lasers (milliwatt power) or focused LEDs to transmit light. This DoD thing seems pretty crackpot to me. Why not just use high frequency microwaves? (Probably around 500 ghz to 1 thz) You have all the bandwidth you could ever use for cellphones in that range, and you wouldn't need fancy optical devices like super-sensitive photodetectors.

      • Re:Using a laser? (Score:3, Interesting)

        by Maddog Batty ( 112434 )
        Lasers produce a very narrow collumnated beam

        Oh I wish....

        Hi powered gas lasers, pumped lasers etc come with a very narrow collumnated output.

        Diode lasers [uk.com], as used in your DVD, CD player, laser pointer etc, come with a highly divergant beam. Say +/-15 degrees in plane of substrate, +/-5 degrees perpendicular. Optics are then used to focus or collumnate the beam. Unfortunately, this is often expensive in small quantities (as much or more than the cost of the laser)
  • Current cellphones are already operating in bands where line of sight is quite critical to half-decent reception. What makes this feasible is that many surfaces are reflective of a lot of bands of EM radiation. This is why we can see things - they reflect light. This is why you can use your TV remote by pointing it away from the set - it bounces off the wall.

    I agree that attenuation will be a big problem, but it's already getting almost that bad as we get higher and higher in the spectru.

    Now, if they could only modulate the sun's rays...
  • "This sounds a little strange to me since you would need a line of site with no obsticals in the way to use this. The article doesn't explain how this might work."

    Four words: Really Really Tall Towers

  • Is this UWB? Are they confusing light with all EM? (Score:5, Insightful)

    by Erpo ( 237853 ) on Wednesday November 27, 2002 @03:36PM (#4769550)
    A different technology in widespread use employs a method called wavelength division multiplexing, in which each cell phone uses a different wavelength of light, according to the researchers. In contrast, optical CDMA would encode each pulse, or bit of information, across a segment of wavelengths. The receiver uses a key to decode the signal and re-create the original pulse.

    This sounds a lot like Ultra Wideband to me. Also, I'm guessing from reading the article that the author is confusing visible light with radio EMR.
  • Holy line of sight, Batman!

    This is just a high-bandwidth version of the bat signal. This technology has been around since the sixties. Hopefully they can make it more portable.
  • - DoD's new "light emitting cell phones" cause massive outbreak of seizures. Spokesman says: "We're really shaken up about this."

    - DoD investigating new "tin can and string" technology for secure landline communications.

  • Hmm (Score:2, Funny)

    by Shdwdrgn ( 162364 )
    Maybe they found a way to modulate the output from the sun? Will probably make those night-time minutes REALLY expensive though!
  • My phone right now is fast enough and secure enough for me. If anyone's listening in, yes I'm going to be home at 5:30 for dinner and I'll pick up the dry cleaning on the way home.
  • Commence massive spelling correction project in
    5...4...3...

  • Easy (Score:3, Funny)

    by uradu ( 10768 ) on Wednesday November 27, 2002 @03:40PM (#4769576)
    The sell phoane comes with a set of special specticals that you put on and look at you're conversashion partner, who has an identicle set up. The phoanes then comunnicate via lazers in the specticals, thats why you have to look at each other.

    (creative spelling purely intentional in homage to the original article)

  • Evil Cell Phones? (Score:4, Funny)

    by ArthurDent ( 11309 ) <meaninglessvanityNO@SPAMgmail.com> on Wednesday November 27, 2002 @03:40PM (#4769578) Homepage Journal
    What I really want is a phone with a freaking laser on it!

  • Said before but, (Score:3, Insightful)

    by Elwood P Dowd ( 16933 ) <judgmentalist@gmail.com> on Wednesday November 27, 2002 @03:43PM (#4769607) Journal
    Someone, either the author, or a source, is totally confused about what light is.

    When I read the topic, it occured to me that they might have been talking about using quantum encryption (photon spin direction? what?) with cell phones. Then I realized it wasn't the year 2025.

    Anyway. This will be interesting when someone who graduated high school writes an article about it.

  • Spectrum (Score:3, Interesting)

    by spoonboy42 ( 146048 ) on Wednesday November 27, 2002 @03:45PM (#4769624)
    It's not necessarily true that you need a line of sight with no obstacles in the way for an optical communications device to work. There are parts of the EM (optical) spectrum which pass through ordinary objects. Infrared, for example, can "bleed through" most walls, allowing infrared photography of the sort sometimes used by law enforcement to see behind closed doors. On the other hand, gamma rays and x-rays, which are very high frequency, are stopped by few things besides lead.

    Actually, current cellphones are, in a way, optical, since they use RF. Radio waves are a kind of light of much lower frequency than the visible spectrum, and they easily leak through all kinds of solid objects. I would assume that this new research project aims at using *higher frequency* optical communications, possibly using a laser for focused rather than diffused (RF-style) transmission. Only transmitting on a direct line of sight has obvious utility for security, and that line of sight doesn't necessarily have to be onobstructed.
    • Please forgive my spelling error, that should read unobstructed, above, and they shouldn't put all those vowel keys right next to eachother on QWERTY keyboards.

    • Re:Spectrum (Score:3, Informative)

      by RealityProphet ( 625675 )

      Optics refers to the range of the electromagnetic spectrum that we can visibly process (400-700nm wavelength). All other wavelengths are not classified as "optical"

      • Re:Spectrum (Score:2, Insightful)

        by zcat_NZ ( 267672 )
        Not true. Optical usually refers to the entire range from IR to UV.. Fibre-optics, CD and DVD, etc are all optical but don't use visible light.

        It'd be nice if the linked article was a little more informative; it doesn't say anything about what part of the 'optical' spectrum these things would use or why spread-spectrum using 'optics' is somehow magically more secure than spread-spectrum using microwave.

  • Some cell phone systems, such as those from Sprint PCS and Verizon Communications, already use a type of CDMA for radio waves, according to the researchers

    We need researchers to tell us that our phones use CDMA? So what ab out all those can you hear me now Sprint CDMA commercials?...must've been an optical illusion :)
  • Looking at the list of CITRIS projects [berkeley.edu], there's all sorts of cool stuff: talking toasters, robot insects, new networking and display technologies.

    Karma whores take note -- Slashdot would probably run stories on anything listed on that page. (You still get points for an accepted submission, right?) Some of them, like the nanotech stress sensor paint and the flying robots sound familiar, but just because they've been linked once doesn't mean they can't be linked twice!

  • The Power of Marketing! (Score:3, Funny)

    by airrage ( 514164 ) on Wednesday November 27, 2002 @03:49PM (#4769662) Homepage Journal
    The article doesn't explain how this might work.

    Of course it doesn't ... that's the power of Marketing! That's why every whitepaper I recieve says that a I should get an ROI return of 663% in 3 years, but wait there's more: if you order now you get free, abosutely free, while supplies last, a neat-o coffee mug! We're not gonna sell this for 299, NO!, 290, NO!, 200 NO!, not even 150, NO!, 100, NO!; that's right for a limited time we will offer this to you, our special customers, at a world-class price of: 3 easy payments of $150! Hurry up and order, you don't wanna miss out!

  • It isn't about optical cell phones (Score:3, Informative)

    by Anonymous Coward on Wednesday November 27, 2002 @03:56PM (#4769702)
    The grant is not to make optical cell phones. The grant is to develop CDMA (a technology used in cell phones) to be used in fiberoptic communications. The title is a bit misleading.
    So, why so much money to port a technology. CDMA allows more effective use of the bandwidth and as the article points out more security than frequency division multiple access. For radio frequency stuff, CDMA is what nearly everyone uses. For radios it requires a wide bandwidth output stage. That is the kicker. The optics guys use fairly narrow band laser output stages. Then the hook them together on the same cable. They don't interfere because they are at different frequencies. To do CDMA with your whole bandwidth requires a wide bandwidth output solution (either a single broadband output or some way to put multiple lowbandwidth stages together in a better way.)

  • Alexander Graham Bell thought of this already (Score:4, Informative)

    by anotherone ( 132088 ) on Wednesday November 27, 2002 @03:57PM (#4769717)
    This is pretty old news. [americaslibrary.gov]
  • This kind of technology is particularly important to the Army for men in the field. The reason is that in the near future, any kind of broadcast RF will result in a bomb down your shorts in a big hurry: smart weapons will home in on any radio frequency they can find, and destroy it. Thus talking on the cell phone, walkie-talkie, whatever, will mean instant death to a soldier.

    Thus the Army must have some kind of non-broadcast communications system. I have no direct knowledge of how they would do it, but it isn't hard to imagine. For example, suppose low-flying satelites broadcast a signal. Handsets on the ground listen for that signal, and then point a highly directional antenna (LASER, focussed RF or microwave, whatever) at the satelite, and then starts transmitting a narrow beam.

    There is not enough economic motive to develop this for purely commercial purposes. But once it is developed for the military, the commercial benefits are there to deploy it. Directional signalling means much less interference, and therefore much less consumption of precious spectrum, and less need for those pesky and expensive cell towers.

    Crispin
    ----
    Crispin Cowan, Ph.D.
    Chief Scientist, WireX Communications, Inc. [wirex.com]
    Immunix: [immunix.org] Security Hardened Linux Distribution
    Available for purchase [wirex.com]

    • "Directional signalling means much less interference, and therefore much less consumption of precious spectrum, and less need for those pesky and expensive cell towers." Yea, instead you will have those small, cheap orbital satellites! Seriously, one of the most significant benefits of low frequency radio communications in battlefield is that radios work through foliage, small terrain obstacles etc.. I wouldn't want to be the "optical radio" guy trying to get a clear shot at some satellite when in a dense forest. With current equipment it is impossible to pinpoint well placed & planned radio positions (perhaps using directional antennas) with means of radio intelligence. The main use of radio intelligence is to get an approximate idea of enemy formations etc., not to send artillery shells on the poor fellow pushing transmit button. In near future (20+ years) it will probably be possible for _US_ to have enough accurate systems to pinpoint enemy transmitters, but even then there won't be enough artillery to put out all those grunts when the action begins and hundreds of radios will start screaming on different frequencies. Using homing missiles for killing grunts with radios would be horrible overkill (and an expensive one), and probably it wouldn't even work as radio transmission are kept as short as possible. Not to mention the deflections of radio waves etc. that would probably send the homing missile of course at some stage. All in all, I don't believe optical communications using satellites will be a viable option in near future battlefield communications. Perhaps when Raczak's Roughnecks get to the field... (Recommended reading: Starship Troopers by Heinlein ;))
      • Homing missiles might be overkill, but a burst from a targeted 50 cal in an overflying drone wouldn't be. In fact, I think all the parts of that project have been done seperately. Whether it hits or not, I bet it wouldn't be long before people stopped using their radios much.
        Hell, for fun they could test it with a paint gun on cell phone users in metro areas...
        "Hello? Hello? Talk louder. What?" /splat...
        -- So, where do we pick up our sigs?

    • Re:Optical Communications to Keep Bombs Away (Score:4, Interesting)

      by Michael Woodhams ( 112247 ) on Wednesday November 27, 2002 @05:59PM (#4770755) Journal
      The problem you describe is not "radio broadcast vs optical narrow beam", it is "broadcast vs narrow beam". Once I've decided to go narrow beam for these reasons, why would I go optical rather than microwave?

      (The beam divergence is inversely proportional to the number of wavelengths wide your transmitter/reflector is, which means that smaller wavelength requires a smaller transmitter apperature to achieve a given beam divergence, but surely microwaves are good enough, and have much better penetration.)
    • Avoiding the "bomb down your shorts" is one of the reasons that the military has been developing and using spread spectrum communications for many years. With DSSS (direct sequence spread spectrum) and a high chip rate, the carrier is spread over a wide swath of spectrum. It can actually be below the noise floor. If you look for the signal with a spectrum analyzer, the most that you will see is a small elevation in the noise level. The tricky part of this is synchronizing the sequence generators in the transmitter and receiver.

  • Soldiers Have Been Carrying Optical Cell For Years (Score:3, Interesting)

    by istartedi ( 132515 ) on Wednesday November 27, 2002 @04:02PM (#4769754) Journal

    From what I hear, every soldier has a mirror. On a sunny day, you can use the mirror to signal aircraft for miles.

    The mirror has the advantage of not needing batteries, being resistant to shock, etc.

    Of course it doesn't work in clouds or dark, and bandwidth, well... leaves something to be desired.

    So if they can do this with infrared and talk through it, that seems perfectly reasonable to me. One advantage of LOS is that you have to get in the way of the thing to jam it. Of course the receiver has to be intelligent enough to ignore signals from the wrong part of town, or signals that don't carry the right code, but it's a solveable problem.

    Of course, any signal, especially an IR laser, gives away your position if the enemy can see it.

    • Re:Soldiers Have Been Carrying Optical Cell For Ye (Score:5, Funny)

      by floydigus ( 415917 ) on Wednesday November 27, 2002 @06:46PM (#4771134)
      It's called a heliograph and a CD would make a very good substitute.
      Take a CD and an ice lolly stick. Make a hole in one end of the stick and hold the CD up in front of your face, shiny side facing out. Be facing the sun, more or less.
      Hold the lolly stick up in front of that (about 12 inches away) and sight through the hole in the CD and the hole in the lolly stick at the aeroplane, boat, visitor craft or whatever you are trying to signal to. Now wiggle the CD until the shadow of the hole in the middle of the CD falls over the hole in the lolly stick. Now you are shining your light right at your target. By flicking your hand, you can turn the light on and off and so make morse. Or binary. Whatever.
      If you do do this to a visitor, they will probably just decode the information on the CD and try to work out the meaning. Do not expect to be rescued. Expect instead to get Barry Manilow's greatest hits beamed back to you some days later.
      If this saves your life, paypal me! ;)
  • "This sounds a little strange to me since you would need a line of site with no obstacles in the way to use this."

    Uh, no...all you'd need is a huge network of mirrors or a lot of little collection points. Use VoIP technology to manage packets of data. Blinks of light work as well as packets of radio and because of their higher frequency they provide more bandwidth.
  • I think this is an ideal technology, that doesn't take up valuable bandwidth in the frequency range we use for radio transmissions.

    'Course, there are drawbacks... You have to stand REALLY still, in just the right spot... ;-)~

  • Reason for developing this... (Score:3, Interesting)

    by klocwerk ( 48514 ) on Wednesday November 27, 2002 @04:16PM (#4769861) Homepage
    People are posting about "why?"
    Consider the havoc that nuclear explosions play with radio frequencies.
    Consider having a method of secure remote communications which does not rely on radio frequencies of any type in such a situation.

    Kinda makes you stop and think about things.

  • Reasoning behind laser phone (Score:4, Informative)

    by randomErr ( 172078 ) <ervin.kosch @ g m a i l .com> on Wednesday November 27, 2002 @04:17PM (#4769869) Journal
    I'm going to dub this the 'Laser Phone'. The Laser Phone will not be made for general public use. Laser Phones will be made for military and corporate entities that require ultra secure communications.

    You maybe asking: âoeWhy would you need such a clunky method of communication? Line of site is not practical.â

    The answer is very simple: Supercomputers and triangulation.

    You see any voice communication has certain pitch and volume amplitude modulations. Pitch and volume amplitude modulations are part language and part human physiology. No matter how you scramble and encode the communication the human voice will always have certain keys that can be easily discerned in a conversation.

    An enemy can easily grab and record a radio signal. Then the digitally recorded file can be feed in a Beowulf cluster of cheap computers. That data can within a few minutes can decode your voice and thus get your tactical information.

    Another advantage of optical communication is that it is almost untraceable. Anytime you use a radio you sending out a beacon saying, "I'm right here; bomb the snot out of me!" An enemy can use simple triangulation to locate you.

    A Laser Phone will be virtually impossible to intercept, track, and decode.

    BTW: Anyone remembers those World War I movies where the soldiers would use mirrors to send Morse code message?

    • No. (Score:2)

      by adb ( 31105 )

      No matter how you scramble and encode the communication the human voice will always have certain keys that can be easily discerned in a conversation.

      gzipped and rijndaeled voice is not voice anymore.

      Triangulation, OTOH, is a meaningful worry.

    • No matter how you scramble and encode the communication the human voice will always have certain keys that can be easily discerned in a conversation.

      An enemy can easily grab and record a radio signal. Then the digitally recorded file can be feed in a Beowulf cluster of cheap computers. That data can within a few minutes can decode your voice and thus get your tactical information.

      Actually, no. Any broadcasted data can be encrypted because it can simply be treated as a block of digital information. Once encrypted, the data, voice or otherwise, is transformed into a stream of pseudo random noise. If the encryption is strong, as it is in many military applications, then it will take far more than a few minutes for a Beowulf cluster to decrypt it!

      But what you said about radio broadcasts being big bomb targets is true, however, and is probably the main impetus behind this optical phone research.
      • I disagree.

        Until you start to communicate with something other then words, you will always have the same basic patterns of communications. Voice is only pitch variation and volume variations. Thatâ(TM)s it, just two factors.

        Yes, you can encrypt a voice message. You can also encrypt a text message. Your voice will always remain the same. You text message may be UPPERCASE, lowercase, a MiX of the TWo, typed in l33t, desrever(reversed), or domo arigoto (a different language). But 'Hi, I'm here, Send supplies' will always be 'Hi, I'm here. Send supplies'.

        Encryption is not a magic bullet. 'Encryption sucks.' ALL Voices have ALL the same constant factors. Any constant is a perfect hook for a hacker to latch onto.
        • You misunderstand what happens in a good encryption system - ENTROPY is added to the information, so any patterns (even encoding the same information multiple times) are not discernable in reasonable amount of time by hacker. And voice will have small variations from one recording to the next, which will result in great chaotic variations in output, so I'll take a well-encrypted VOICE pattern over a TEXT one if I knew text or message was very likely to be similar from one transmission to the next.
    • Actually, You've touched on why the navy still uses spotlights to communicate to this day. You know those movies where you have some seamen flipping the shades on a spotlight to send morse code to another ship? That's what I'm talking about. Unless you are along the line of sight which the light beam is travelling, it's virtually impossible to intercept the signal.

  • DISCO BALLS! LOTS AND LOTS OF DISCO BALLS! (Score:3, Funny)

    by Viewsonic ( 584922 ) on Wednesday November 27, 2002 @04:33PM (#4769978)
    I'm busting out Beejee's when I get home for ThanksGiving. I can't wait for this!!
  • If you read my 'rolling data center' comment earlier you know I was talking about walking around festooned with digital stuff.

    Optical MIGHT be the way for all these to communicate IF bluetooth crashes and burns AND people get nervous about all that radio radiation around them, and only one good cancer report might do it, AND it's only used on items that have a line of sight with each other AND they can make it secure (easy but will it be done?)

    This might be an answer looking for a problem it will never find...

  • optic commercials (Score:2, Funny)

    by Anonymous Coward
    can you see me now? good.
    can you see me now?
  • all you need is mirrors...mirrors will be everywhere...and behind those mirrors will be clones of tom ridge on john ashcroft. oh the end is near.

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