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Privacy Technology

Matchstick-Sized Sensor Can Record Your Private Chats Outdoors 90

Posted by Soulskill
from the just-in-case-your-paranoia-was-wearing-off dept.
wabrandsma sends this story from New Scientist: "A sensor previously used for military operations can now be tuned to secretly locate and record any single conversation on a busy street. [A] Dutch acoustics firm, Microflown Technologies, has developed a matchstick-sized sensor that can pinpoint and record a target's conversations from a distance. Known as an acoustic vector sensor, Microflown's sensor measures the movement of air, disturbed by sound waves, to almost instantly locate where a sound originated. It can then identify the noise and, if required, transmit it live to waiting ears. Security technologist Bruce Schneier says this new capability is unwelcome – particularly given the recent claims about the NSA's success at tapping into our private lives. 'It's not just this one technology that's the problem,' Schneier says. 'It's the mic plus the drones, plus the signal processing, plus voice recognition.'"
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Matchstick-Sized Sensor Can Record Your Private Chats Outdoors

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  • Yawn (Score:3, Interesting)

    by ArchieBunker (132337) on Saturday September 28, 2013 @06:52PM (#44981947) Homepage

    Gene Hackman was doing this in the 1970's http://www.imdb.com/title/tt0071360/?ref_=sr_1 [imdb.com]

  • I can imagine the same people collecting all of our online data now adding offline conversations to it. Imagine adding this to an insect sized flying drone and releasing many of them into your city. The could go anywhere and record anything.
  • by Anonymous Coward on Saturday September 28, 2013 @07:05PM (#44982033)

    While the sensor measures the vector direction of sound, it measures the *SUM* of all sounds impinging on that point. With a single point sensor, you can't separate the direction of a particular one.

    Now, a reasonably small array of these sensors (maybe as small as 30cm across) might be able to accurately localize the source, in the same way that your brain can tell what direction a sound is coming from with just two ears.

    Of course, it will also be confused by multipath and reflections, although if adequately characterized, those could be used for localization as well, since the reflected paths have different spectral properties.

    There are LOTS of sensors that are tiny and easily deployed these days, using all sorts of sensing modalities. And processor horsepower and tiny comm to get the signals to the processor are easier to get too.

    Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land. I actually would have more concerns about private industry: they're not subject to most privacy laws (at least in the U.S.): The wiretap laws, for instance, refer only to comms over a system. If you want to set up a big acoustic array at the beach and record everyone's conversations, process it, and sell the product to whoever, that's perfectly legal. Or set that array up out on the pubic street in front of your house, or the thermal imaging camera, or the mmWave wall penetrating radar or whatever.

    So, it's those laws and common decency is where the efforts should concentrate.

    • by ATMAvatar (648864) on Saturday September 28, 2013 @07:41PM (#44982207) Journal

      Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land.

      What governments would those be which are restrained by the law, let alone common decency?

      • by Jah-Wren Ryel (80510) on Saturday September 28, 2013 @09:01PM (#44982551)

        What governments would those be which are restrained by the law, let alone common decency?

        A representative government is a product of the law so of course it is restrained by the law. Just because individual actors within the government aren't 100% restrained by the law does not invalidate the principle that a representative government operates within the law.

        The alternative to your nihilism is pure might-makes-right. Don't let the perfect be the enemy of the good.

        • In ideal principle I think you are correct. However, recent evidence would indicate that somewhat more than a few individual actors are considerably less than 100% restrained.

          There are alternatives to both the status quo and nihilism. Do not let rhetorical absolutism be the enemy of practical observation and action.

    • by SuricouRaven (1897204) on Saturday September 28, 2013 @07:46PM (#44982249)

      And budget. Monitoring people used to require paying someone to listen to the tapes. The advent of computers has greatly brought down the cost of mass-monitoring by allowing the computers to sift through the vast collection and just flag the potentially interesting things for human examination.

      • by greenbird (859670)

        allowing the computers to sift through the vast collection and just flag the potentially interesting things for human examination.

        Or allowing them to go back and review every bit of communication you ever been involved in once they decide you're "a person of interest".

    • by Anonymous Coward on Saturday September 28, 2013 @07:52PM (#44982273)

      I think the coarse hair would block the sound waves on a pubic street, thus rendering the technology useless.

    • by ebno-10db (1459097) on Saturday September 28, 2013 @07:53PM (#44982277)

      Governments have always had the technical means to be invasive, they are restrained by common decency and the law of the land.

      They are?

      If you want to set up a big acoustic array at the beach

      Were I to surveil the beach, I'd be more interested in visual than auditory information. YMMV.

      All joking aside, I'm skeptical of the technical claims of superiority, other than small size. That's tempered by my lack of knowledge of acoustics. I think of it in terms of analogies to optics or radar (as a physicist I once knew said, a wave is a wave is a wave). You need an array to locate the direction something is coming from. Roughly speaking the larger the array relative to the wavelength, the more precisely you can determine direction, and the more you can spatially filter that source from other sources. You can do that with small optical sensors (e.g. a camera or your eye) only because of the short wavelength of light. Radar antennas with the same directionality and resolution need to be much larger. At 1kHz (a frequency you definitely need to understand conversation) the wavelength of a sound wave is 343mm. For radio waves that's the wavelength you'd get at 875MHz. You need a fairly big antenna to get decent resolution. That can be accomplished by widely spaced sensors (antenna elements, whatever) and some serious signal processing. I don't see how one of these sensors can have any serious directionality by itself, or having three in the same place pointing at x, y and z directions can do much.

      One difference I can think of between electromagnetic radiation and sound waves is that the former are transverse waves and the latter are longitudinal waves. Does that make much of a difference for these purposes?

      • by fa2k (881632) <pmbjornstad @ g m a il.com> on Saturday September 28, 2013 @09:28PM (#44982663)

        One difference I can think of between electromagnetic radiation and sound waves is that the former are transverse waves and the latter are longitudinal waves. Does that make much of a difference for these purposes?

        It's been explained already by Solandri but I'll give it a try. The sensor measures the displacement of the air, not the pressure. The GP post argues that it measures the vector sum of the displacement caused by all sounds, and this is correct. I imagine a small light ball that's magnetically suspended and being pushed around by the air, and the movement of the ball is recorded (this is probably not how it's done, I imagine it would have a highly non-linear frequency response). If there are two sounds from different directions with different frequencies, you could easily tell them apart -- e.g. the ball is moving up and down fast, and left and right slowly. If the sources have the same frequency, or it's just some broadband noise, you can't tell them apart. You could probably do it easily with two vector sensors and relative timing, but the whole point was that you can do it with one sensor in plausible conditions.

        As for electromagnetism / sound, you are right that the transverse/longitudinal distinction makes a difference. The air displacement is analogous to the electric field. An RF antenna sort of measures the projection of the electric field onto some given axis, and an omnidirectional antenna measures approximately the absolute value of the electric field. (A mic may measure pressure, not displacement, but these are alternative variables for discribing the same wave). An analogous RF detector to the sound vector sensor would be three small linear antennae pointing in linearly independent directions, measuring the x,y and z components of the electric field as functions of time. The transverse / longitudinal distinction comes in here: the EM waves have an additional degree of freedom, namely polarisation. The E field can point in any direction perpendicular to the direction of propagation. Given the polarisation vector you can thus only constrain the vector to the source to a plane.

      • by sumdumass (711423)

        I don't think this sensor works in the traditional sense that you are familiar with. It is inferring information about a wave from the wave itself as it passes through the air. It actually looks at the medium the wave travels through itself and how the waves interact with it's surroundings not what the waves represent or the information it carries. Think of it more like your surround sound system when you connect a mic in the middle of the sitting area and the speaker timing is adjusted so the sound is cent

    • Note to old school eavesdroppers: don't get rid of all your parabolic dish microphones just yet.

    • by citizenr (871508)

      multipath and reflections

      are already used in DSP to model rooms and sometimes even to reconstruct 3D shape from sound alone

    • by FatdogHaiku (978357) on Saturday September 28, 2013 @08:28PM (#44982451)

      ... If you want to set up a big acoustic array at the beach and record everyone's conversations, process it, and sell the product to whoever, that's perfectly legal...

      Unless you are openly and obviously (to the subjects being recorded) voice recording, most states don't allow the type of action you posit there. At least ONE party from each conversation has to consent to any recording and in 12 states EVERYONE must consent. There are limited "Presumed Consent" exceptions but a public beach would not be one of them. There is a quick review here:
      http://www.wingfieldaudio.com/surreptitious-recording.html [wingfieldaudio.com]
      Not sure about "through the walls" video/audio recording but I'd bet peeping tom laws would be made to suffice...

    • by Solandri (704621) on Saturday September 28, 2013 @08:56PM (#44982539)

      While the sensor measures the vector direction of sound, it measures the *SUM* of all sounds impinging on that point. With a single point sensor, you can't separate the direction of a particular one.

      That's true for a single snapshot of sound in any given instant. But if you collecting acoustic data over a period of time, transient sounds (noise) average out, and the loud peak (gunshot) or cyclical nature (engine) of certain sounds of interest should ease their extraction, with sufficient processing.

      Now, a reasonably small array of these sensors (maybe as small as 30cm across) might be able to accurately localize the source, in the same way that your brain can tell what direction a sound is coming from with just two ears.

      That was my impression too (one of my grad school courses was on acoustics and sonar design). That's what they do in submarines - make a great big phased array microphone. But if you follow the link in TFA to the company's site, they have a PDF which gives a bit more info on how their sensors work:

      The Microflown sensor is based upon MEMS technology , and uses the temperature difference in the cross section of two extremely sensitive heated wires to determine acoustic particle velocity . Assembling three orthogonally placed Microflown sensors in one single point, a very compact Acoustic Vector Sensor can be produced.

      So whereas a phased array sensor works by comparing the arrival times of a wavefront at different locations to determine the direction the wavefront is traveling, it sounds like their gizmo is measuring in 3 dimensions the actual movement of air molecules caused by the sound wave, and deriving the wavefront travel direction from that.

      • it sounds like their gizmo is measuring in 3 dimensions the actual movement of air molecules caused by the sound wave, and deriving the wavefront travel direction from that

        Intuitively I can see how that works (although intuition isn't always good physics of course). But if you could get decent resolution this way, why don't they use something like this on subs instead of large phased arrays? Acoustic waves in both air and water are longitudinal waves, so you should be able to sense direction the same way. It seems like the inventive part of this thing is the MEMS technique, the heated wires, etc. I find it hard to believe that with lots of room and power available (e.g. on a

      • I have a feeling that these could easily be fooled by placing several speakers which emit variable barely audible sounds whit are emitted at random times of random frequency and of random length and changing volume.

      • by hankwang (413283)

        But if you collecting acoustic data over a period of time, transient sounds (noise) average out, and the loud peak (gunshot)

        Well yeah, if you want to pinpoint the source of a massive transient or the source of an annoying continuous whistling sound or a never-ending repeated playback of some secret message, this sensor could work. But it would not be very useful for recording private conversations.

        But look at it from this side: a normal microphone measures pressure as a function of time, i.e. p(t). If the

    • I always hear this garbage from Anti-Corp types. Here's the big takeaway: If a corporation does something bad, you can sue or regulate them out of business. If your government does something bad, they can choose to Ignore the law or pass an exception for themselves. And, btw, who's violating privacy on an scale these days? Uncle Sam.

    • I looked at the company's web site. The technology description indicates that the sensor is a coplanar parallel pair of tiny hot wire anemometer elements located very close together. This structure measures the component of air velocity that is across the wire pair, in the wire pair's plane. Three of these sensors, mounted so they're mutually orthogonal (one each in the XY, XZ, and YZ planes) give the full vector field for air velocity. There is another co-located sensor that gives the pressure (intensity).

  • by GIL_Dude (850471) on Saturday September 28, 2013 @07:14PM (#44982065) Homepage

    'It's not just this one technology that's the problem,' Schneier says. 'It's the mic plus the drones, plus the signal processing, plus voice recognition.'"

    I usually agree with Bruce. But unless that quote was taken way out of context, he is wrong here. Technology isn't the problem. It never is. It is the people salivating at the thought of using it against us. Even those who think they are doing us a service to keep us safe: when they invade our privacy, they are the problem. The tech? It's actually cool. There are probably - how would someone jaded to the world of sound and copyright put it - many non-infringing uses of the tech. It can probably even be used in a way that isn't spying. For example recording a conference speaker (with permission) in a noisy room or the like.

    • by techno-vampire (666512) on Saturday September 28, 2013 @07:59PM (#44982311) Homepage
      This is one case where I do agree with him, probably because I think I know what he was thinking when he said this: it's not just one technology, or even one set of technologies that's the problem. It's the fact that this set of gadgets can be combined to make something that can be used for invasive surveillance of whoever some government agency thinks needs watching combined with what appears to be a pervasive attitude in those agencies that they have the right to snoop on anybody, any time, any place for whatever reason they want without any substantive oversight.
  • by aNonnyMouseCowered (2693969) on Saturday September 28, 2013 @07:26PM (#44982127)

    ...everybody has it. The last thing we need is awesome tech only spies and generals possess (weapons of mass destruction/contamination being a notable exception). So yes, this is unwelcome technology, but since it's already there, we might as well let everybody have it.

    • by Kjella (173770) on Saturday September 28, 2013 @08:03PM (#44982337) Homepage

      No, having the lack of privacy go both ways isn't as good as having privacy. A system where nobody can keep their actions private is a system governed by mob rule, nobody wants to engage in socially unacceptable behavior because they're instantly shunned and those who fail to participate in the shunning are also shunned for condoning it. Nobody will speak out unpopular opinions even if they feel it ought to be said, because those who don't like the message will go after the messenger. All social circles become totally transparent and people will self-censor their associations to avoid social stigma. It's freedom of the "you have freedom of speech and can say what you want, but we'll shoot you afterwards" variety.

      Not to mention, it won't work. The powers to be will always find some reason why their conversations must be protected in the name of national security - after you've given up yours in the name of national security, of course. And if you don't like it you've got something to hide and is probably one of the bogeymen we're trying to catch. They can clam up any time they feel like it, while you'll stay stripped bare. Only the truly naive wants to head us in that direction, because <Admiral Ackbar>It's a trap!</Admiral Ackbar> and a pretty obvious one at that.

      • by nut (19435)

        GP's argument:

        The last thing we need is awesome tech only spies and generals possess...

        Your argument:

        No, having the lack of privacy go both ways isn't as good as having privacy.

        Which is shooting down a different position to the one the GP took. No one is arguing that privacy for all isn't the best situation. But this technology now exists, so the genie is out of the the bottle and that option is almost certainly off the table.

        We now get to choose between the option where a small powerful elite has this technology, and the option where everyone has it.

        I, for one, prefer the latter.

        • by Kjella (173770)

          We now get to choose between the option where a small powerful elite has this technology, and the option where everyone has it.

          Sorry, but just because the NSA has been listening in on everyone's phone calls doesn't make it a good idea to let everyone listen to everyone else's phone calls. The right choice is to make the NSA stop, even if the technology as such exists. It doesn't mean we have to embrace it, we already have many ways of planting stealth microphones and none of them have much legitimate use. I don't see how this one is very different.

      • A system where nobody can keep their actions private is a system governed by mob rule, nobody wants to engage in socially unacceptable behavior because they're instantly shunned and those who fail to participate in the shunning are also shunned for condoning it. Nobody will speak out unpopular opinions even if they feel it ought to be said, because those who don't like the message will go after the messenger. All social circles become totally transparent and people will self-censor their associations to avoid social stigma. It's freedom of the "you have freedom of speech and can say what you want, but we'll shoot you afterwards" variety.

        Sounds like Slashdot or Facebook ;)

        Seriously, though, things never go out to their theoretical extremes like that. If effective technical countermeasures are not developed, then socially what will happen (yes, in fits and starts with much upheaval and not smoothly) is that people in general will simply have to get used to the fact that other people will often say things that they don't like.

    • "The last thing we need is awesome tech only spies and generals possess (weapons of mass destruction/contamination being a notable exception). "

      Just curious - why do you exclude these (weapons of mass destruction) from your definition of technology=good if everybody has it? It suggests you are declaring that the declaration that technology should be accessible to all is qualified by value judgements - who gets to make the judgement call? you, me, random person in Afghanistan/Bolivia/Estonia? the UN?

      If nucle

  • by roc97007 (608802) on Saturday September 28, 2013 @09:31PM (#44982681) Journal

    ...in inventing a language. I think it's high time we addressed the tweepadoc in the room.

    • by Anonymous Coward

      any substitution-type encryption is easily hacked. See rot-13 as an example (word-wise takes a little longer).

      • by roc97007 (608802)

        I understand. Mere word substitution wouldn't do it. It'd have to be something more complicated, with a new, perhaps variable syntax, and a vocabulary where words mean completely different things in slightly different usages.

        And make it sound like slang for some additional camouflage. And include meaningful sounds that would normally be considered background noise. Hmm.

  • On earth. Up here in space I'm looking down on you. My lasers trace Everything you do. You think you've private lives Think nothing of the kind. There is no true escape I'm watching all the time. I'm made of metal My circuits gleam. I am perpetual I keep the country clean. I'm elected electric spy I'm protected electric eye. Always in focus You can't feel my stare. I zoom into you You don't know I'm there. I take a pride in probing all your secret moves My tearless retina takes pictures that can prove. I'm
    • by Anonymous Coward

      (c) Judas Priest FTFY

  • by 140Mandak262Jamuna (970587) on Saturday September 28, 2013 @10:56PM (#44982993) Journal
    I think it would be New England Patriots coach who really really wanted this.
  • Available since 2010 (Score:4, Informative)

    by Animats (122034) on Sunday September 29, 2013 @12:42AM (#44983411) Homepage

    "Acoustic zoom" beam-forming microphones [sqhead.com] have been available since 2010. Their main commercial product is an "acoustic camera" with 128 microphones on an 0.4 meter disk. They have other surveillance products [sqhead.com], but they are "not approved for unlicensed users". This is already in use at FCI Otisville [fbo.gov], a US prison. "This technology allows an operator to listen to various locations within the range of the system without any movement of the equipment. ... (T)his ability means the operator does not have to move about in order to "point" the equipment at his target and thereby draw attention to him potentially compromising the investigation."

    With these systems, if you have enough recording bandwidth, you can record all the microphones and do the beam-forming later. So it's possible to pick the target at playback time. Squarehead is partnering with Galleon Embedded Computing, which makes 8 terabyte recorders full of flash devices capable of recording at gigabit Ethernet rates, so that's presumably what they're doing.

    There are several other vendors now. This isn't really that hard to do.

    So this technology is already out there, listening to crowds and pulling out single conversations.

  • by photonic (584757) on Sunday September 29, 2013 @04:30AM (#44984083)
    I remember seeing a presentation by these guys when they were probably still a recent startup company at Twente University, must have been around 15 years ago. Their sensor is build with MEMS technology and consists of 2 or 3 tiny wires (maybe 1x200 micron) that are suspended over a valley etched out of a silicon wafer. When these wires are heated up, a sideways airflow will cause tiny difference in temperature between the wires that can be read out by measuring the resistance. At the time, their target application was low-cost microphones for use in mobile telephones. IIRC, the sensitivity of this sensor had a sensitivity that rolls off as 1/f inherent to the involved physics and they were struggling with the noise at high frequencies in the reconstructed sound. Looking at their website, the sensor still looks exactly the same. Assuming no major breakthrough (I could imagine they lowered the noise by a factor 10 meanwhile, but not that they solved the 1/f problem), I guess the major change now is that they can do more fancy signal conditioning with a DSP in real time. Too bad they went for the military market, but I guess that is a way to slap a few 10-Euro sensors together and sell them as a 10kEuro package. Does anyone know what could be done with these direction sensitive flow-sensors that cannot be done with a phased-array of conventional microphones?

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