Bunnie Huang has published a reference design for a near-ultrasound data link.
We were requested to investigate “near ultrasound” (NUS) links as part of our research on developing the Simmel reference design for a privacy-preserving COVID-19 contact tracing device. After a month of poking at it, the TL;DR is that, as suspected, the physics of NUS is not conducive to reliable contact tracing. While BLE has the problem that you have too many false positive contacts, NUS has the problem of too many false negatives: pockets, purses, and your own body can effectively block the signal.
That being said, we did develop a pretty decent-performing NUS data link, so we’ve packed up what we did into an open source reference design that you can clone and use in your own projects.
Previously:
(2020) Your Apps Can Pick Up Ultrasonic Signals You Can't Hear
(2017) Ultrasound Tracking Could be Used to Deanonymize Tor Users
Related Stories
Ultrasounds emitted by ads or JavaScript code hidden on a page accessed through the Tor Browser can deanonymize Tor users by making nearby phones or computers send identity beacons back to advertisers, data which contains sensitive information that state-sponsored actors can easily obtain via a subpoena.
This attack model was brought to light towards the end of 2016 by a team of six researchers, who presented their findings at the Black Hat Europe 2016 security conference in November and the 33rd Chaos Communication Congress held last week.
Their research focuses on the science of ultrasound cross-device tracking (uXDT), a new technology that started being deployed in modern-day advertising platforms around 2014.
uXDT relies on advertisers hiding ultrasounds in their ads. When the ad plays on a TV or radio, or some ad code runs on a mobile or computer, it emits ultrasounds that get picked up by the microphone of nearby laptops, desktops, tablets or smartphones.
These second-stage devices, who silently listen in the background, will interpret these ultrasounds, which contain hidden instructions, telling them to ping back to the advertiser's server with details about that device.
-- submitted from IRC
High-frequency audio could be used to stealthily track netizens
Technical folks looking to improve web privacy haven't been able to decide whether sound beyond the range of human hearing poses enough of a privacy risk to merit restriction.
People can generally hear audio frequencies ranging from 20 Hz and 20,000 Hz, though individual hearing ranges vary. Audio frequencies below and above the threshold of human hearing are known as infrasound and ultrasound, respectively.
[...] A warning from America's trade watchdog, the FTC, in 2016 and research published the following year identifying 234 Android apps listening covertly for ultrasound beacons, helped discourage inaudible tracking.
Several of the companies called out for these privacy-invading practices, such as SilverPush, have moved on to other sorts of services. But the ability to craft code that communicates silently with mobile devices through inaudible sound remains a possibility, both for native apps and web apps. Computer security researchers continue to find novel ways to use inaudible audio for data exfiltration. And ultrasound is still used for legitimate operations – Google's Cast app, for example, relies on an ultrasonic token when pairing with a nearby Chromecast.
[...] Weiler raised the subject three weeks ago – one element in a larger debate about reducing the fingerprinting surface of the Web Audio API. And last week, the discussion thread was closed by Raymond Toy, a Google software engineer and co-chair of the W3C's Audio Working Group.
Toy argued that if a developer is allowed to use a specific audio sampling rate, no additional permission should be required – few users enjoy dealing with permission prompts, after all. And other web developers participating in the debate expressed concern that limiting available frequency ranges could introduce phase shifting or latency and that there's no sensible lower or upper threshold suitable for everyone.
(Score: -1, Troll) by Anonymous Coward on Friday July 10 2020, @11:49PM (11 children)
Sane people call it "sound". But then again, this is a woman whose parents named her Bunnie.
(Score: 1, Informative) by Anonymous Coward on Saturday July 11 2020, @12:54AM (3 children)
Bunnie Huang is a guy, an MIT prodigy best known for cracking the original Xbox's security via 'glitching', which lead to the next two generations of modchips targetting the Original Xbox and the 360. He then went on to create the Chumby, then the Novena 'open hardware' laptop and since then has been doing all kinds of electrical engineering work out of Shenzen and then Singapore for the past 10+ years.
Maybe if all you have to add to the conversation is a bunch of comments showing how retarded you are, you should go register an account on the green site and tell everybody how you support Nvidia because AMD's Lisa Su is really a dude.
(Score: 2) by c0lo on Saturday July 11 2020, @01:06AM
Even more, "bunnie" (with 'b' in lower case!) is his hacker nickname [wikipedia.org]
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: 0) by Anonymous Coward on Saturday July 11 2020, @01:09AM (1 child)
So basically someone who creates products that add no value to society and quickly end up in landfills. First against the wall when the revolution comes.
(Score: 0) by Anonymous Coward on Saturday July 11 2020, @11:02AM
At least he does something creative with his life and makes a lot of money on the side.
Whereas you're more of a torches-and-pithforks guy, I get the impression. They kind the carries civilization to new heights.
(Score: 2) by c0lo on Saturday July 11 2020, @01:10AM (6 children)
I guess your sane people call "near infrared" just "red", eh?
(bloody idiot, a waste of breathing space)
https://www.youtube.com/@ProfSteveKeen https://soylentnews.org/~MichaelDavidCrawford
(Score: -1, Troll) by Anonymous Coward on Saturday July 11 2020, @01:22AM
Whoosh! Just waiting for pink-hair SJW to make irate comment about genderist post and OP has hit the trolling trifecta.
(Score: 2) by HiThere on Saturday July 11 2020, @03:37AM (4 children)
Somehow sounds don't seem to have spectral names the way colors do, so you can't call it indigo. But you could list a range of frequencies (specified by musical pitch for ready interpretation). I probably wouldn't be able to hear it, so to me it would probably be sound. That six year old over there might well hear it just fine, and be first intrigued and then annoyed. And my dog .... well, stereotypes to the contrary, she probably wouldn't be able to hear it, as she's 15 years old and getting a bit deaf.
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by HiThere on Saturday July 11 2020, @03:39AM
Agggh...
change "so to me it would probably be sound."
to "so to me it would probably be ultra-sonic sound."
Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
(Score: 2) by FatPhil on Saturday July 11 2020, @07:28AM (2 children)
So it's ultrasound, but only just. Or near-ultrasound to use the preferred technical name.
It's an easy terminology to adopt and adapt - for example, the OP is a near-untertroll.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Saturday July 11 2020, @07:46AM (1 child)
Give him a chance, likely he's a wannabe troll.
(Score: 0) by Anonymous Coward on Saturday July 11 2020, @11:05AM
Is it still "feeding the troll" if you troll the troll into more trolling, without him (her??) realizing he's himself being trolled?
Is counter-trolling a societally acceptable activity?
(Score: 2) by VLM on Saturday July 11 2020, @02:21PM
The idea of data carried over plain old sound link is like moth to flame for tech people.
Historically for decades now the standard way to demonstrate various ham radio data modulations, most famously PSK31 back when it was new and FT-series stuff now, is just two laptops running the sound modems with speaker and laptop microphone in free air.
Its not exactly hard to set two laptops to 13 KHz or any frequency low enough for the laptop hardware to operate and talk across the room digitally or send FAXes or slow scan TV. Obviously error correcting systems like FEC AMTOR or packet are a bit more error free than classic 1950s FSK RTTY.
For many years the broadcast engineers know all about this weird data carrier they transmit for ratings tracking.
I'm just saying someone "invents" sending data in free space over speakers roughly every 30 to 45 days for many decades now.
Generally I'd say based on experience that free space data transmission is slower but more reliable than turn of the century IRDA, and shorter range and slower yet easier to set up than bluetooth serial RFCOMM protocol.
Its fun and all you need is two computers (raspi?) with some pretty simple software to experiment.
Note that ham radio operators are used to the sounds and find slow speed fsk rtty or multi-tone "modern" modes to be melodious whereas things like 60 lpm fax are rhythmic and generally OK to hear, whereas the general public hears the whine of a nice multi-level QAM and scream "shut that GD noise down it hertz (ha ha) my ears"