from the your-android-needs-to-be-more-paranoid dept.
The Register has a story on a new technique which turns commodity devices with microphones and speakers into active sonar systems
The technique, called CovertBand, looks beyond the obvious possibility of using a microphone-equipped device for eavesdropping. It explores how devices with audio inputs and outputs can be turned into echo-location devices capable of calculating the positions and activities of people in a room.
In a paper [PDF] titled "CovertBand: Activity Information Leakage using Music," Rajalakshmi Nandakumar, Alex Takakuwa, Tadayoshi Kohno, and Shyamnath Gollakota describe a way to transmit acoustic pulses in the 18‑20 kHz range, masked by music, from the speaker and tracking sound reflected by the human body using microphones
The project home page includes further details, and the paper details proof of concept implementations on an Android and Smart TV device, which demonstrate both accurate tracking, and the ability to infer information about what the target is doing.
(Score: 2) by MrGuy on Tuesday August 22 2017, @03:28PM (2 children)
...that Batman was right [youtube.com] all along.
Now where's my grappling hook?
(Score: 0) by Anonymous Coward on Tuesday August 22 2017, @04:28PM
You only want to trick us into playing the sound associated with that video, so that you can echo-locate our surroundings! ;-)
(Actually, using specifically that video for that purpose would be hilarious.)
(Score: 0) by Anonymous Coward on Wednesday August 23 2017, @03:40AM
Yes, even more right than you want to admit. [youtube.com]
(Score: 1, Insightful) by Anonymous Coward on Tuesday August 22 2017, @03:36PM (2 children)
Back in the day, we'd say things like "I'm afraid the government is trying to put us under constant surveillance"; these day we say "Hey surveillance, order me 5 trinkets and turn up the volume"
But they let keep your little guns, so I guess you got that going for you...
(Score: 1) by Virindi on Tuesday August 22 2017, @03:43PM (1 child)
Only with constant protest.
(Score: 0) by Anonymous Coward on Tuesday August 22 2017, @08:42PM
Yes, they'll know what you have and if you happen to be wielding one when they arrive. Isn't technology and freedom great?
(Score: 0) by Anonymous Coward on Tuesday August 22 2017, @04:20PM (4 children)
generators specifically for the 18-20khz range at ~10dB over the highest output device that will be in the room?
(Score: 0) by Anonymous Coward on Tuesday August 22 2017, @04:32PM
Alternatively, put a filter between the amplifier and the speaker which filters out anything in that frequency range.
(Score: 3, Funny) by bob_super on Tuesday August 22 2017, @06:06PM (1 child)
It's called "children".
(Score: 0) by Anonymous Coward on Wednesday August 23 2017, @03:42AM
That's raycis.
(Score: 2) by MrGuy on Tuesday August 22 2017, @06:15PM
I'm not sure a white noise generator will help with this problem. It might even make it worse.
The idea (as I understand it) is to use sound (coming from a static location) and a microphone (also in a static location) to "map" physical details of the space, and potentially detect when they change. A white noise generator that doesn't move is just another source of sound that can be used for the mapping. Unless you want to use enough power to effectively overload the detector, which I guess could work. But the article also notes that sounds in this band, while themselves inaudible, can be detected by the way they interact with higher harmonics of otherwise audible sound. They talk about which kinds of music you can "hide" the signal in, which implies that having a noise generator going full time could affect the sounds you can actually hear.
A better idea (to my mind, anyways), would be to use a technology similar to what's used in active noise cancelling headphones. Noise cancelling headphones have a microphone to detect sound, and very quickly create a "counter" wave of sound from a speaker in the headphones that's carefully timed to arrive simultaneously with the noise, thus cancelling it out audibly. Active noise cancelling depends on precise timing, which means there's a slight and very precise delay between the microphone hearing the noise, and the speaker creating the counter noise - otherwise they'd arrive off-phase and you'd have WORSE noise. To use that for a jammer, you'd want a combination microphone and speaker that used a variable (and constantly changing) delay factor to repeat the source signal back out. This would create false "echoes" that would make the mapping inaccurate. And if, over time, the delay changes slightly, then the distortion introduced will not be easy to control for over time.
(Score: 2) by RamiK on Tuesday August 22 2017, @09:03PM
https://www.youtube.com/watch?v=h5wbGjdSHUs [youtube.com]
Elderly edition: https://www.youtube.com/watch?v=4uoOls8gO-Y [youtube.com]
And a little something for the kids: https://www.youtube.com/watch?v=1lsnTQyGI78 [youtube.com]
compiling...