Company embeds inaudible sounds in web pages to identify users across devices - Page 1
Forum section: electronics / general

author: cdev
author_rank: Super Contributor
timestamp: January 05, 2019, 02:56:44 pm
content: This may work fine, but it seems truly evil and creepy to me.http://arstechnica.com/tech-policy/2015/11/beware-of-ads-that-use-inaudible-sound-to-link-your-phone-tv-tablet-and-pc/

author: Raj
author_rank: Frequent Contributor
timestamp: January 05, 2019, 03:49:50 pm
content: let our next project be -random ultrasound emitter

author: cdev
author_rank: Super Contributor
timestamp: January 05, 2019, 04:05:42 pm
content: Agreed!Quote from: Raj on January 05, 2019, 03:49:50 pm

author: Domagoj T
author_rank: Frequent Contributor
timestamp: January 05, 2019, 04:42:43 pm
content: While there is nothing fundamentally impossible about this, it sounds unlikely. Not only would you need the speakers capable of reproducing ultrasound, but also an ultrasound sensitive microphone and an always-listening software (spyware) on the receiving end.

author: cdev
author_rank: Super Contributor
timestamp: January 05, 2019, 08:37:03 pm
content: I suspect that they might actually be using infrasound, not ultrasound. (see below for an example of low frequency modification of a condenser mic. )Or very short sounds we might never notice. In any case, I personally am not brushing it off as impossible or implausible. If I was somebody whose job it was to prevent data exfiltration from a computer the first things I would do is physically remove microphones, speakers, wifi and Bluetooth hardware from a computer or cut the power going to them.I would also put the computer inside of a metal box.Sensors (Basel). 2011; 11(1): 623–637.Published online 2011 Jan 10. doi: 10.3390/s110100623PMCID: PMC3274121PMID: 22346594Response Identification in the Extremely Low Frequency Region of an Electret Condenser MicrophoneYih-Nen Jeng,* Tzung-Ming Yang, and Shang-Yin Leehttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC3274121/Such microphones are also useful for evaluating people's health status.Quote from: Domagoj T on January 05, 2019, 04:42:43 pm

author: Zero999
author_rank: Super Contributor
timestamp: January 05, 2019, 09:08:13 pm
content: Quote from: cdev on January 05, 2019, 08:37:03 pmBut that would need large woofers and amplifiers with large enough coupling capacitors to pass infrasonic frequencies. I think ultrasound would be easier.

author: RoGeorge
author_rank: Super Contributor
timestamp: January 05, 2019, 09:28:49 pm
content: Quote from: Domagoj T on January 05, 2019, 04:42:43 pmIt is possible and in use for a long time (maybe not commercially).I guess the most famous known example was the case in which an underground network of child pornography was shut down. To identify the persons involved for sure, the sound emitted by the webpage was matched with the sound received by the suspected mobile phones. It was in the mainstream media at the time.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: January 05, 2019, 10:57:07 pm
content: I don't remember ever hearing about it. Can you give more details?

author: RoGeorge
author_rank: Super Contributor
timestamp: January 06, 2019, 12:25:53 am
content: Now that you asked, I realized that I don't remember the details of the scandal/story for sure. I don't even recall if I read about the children story, or seen it in a video/documentary, maybe some hacking conference, I don't know, sorry.If you are asking about the technical details (and not the scandal story), the technique is called Cross-device tracking:https://en.wikipedia.org/wiki/Cross-device_tracking

author: MrMobodies
author_rank: Super Contributor
timestamp: January 06, 2019, 02:23:01 am
content: So on a phone the "apps" will gain absolute control of my volume control and microphone to make and record sounds that I can't hear even if I have them muted.It is good I don't have a microphone plugged in.I wonder if they are also going use it to experiment with subliminal messaging.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: January 06, 2019, 05:22:21 am
content: Quote from: MrMobodies on January 06, 2019, 02:23:01 amThere is absolutely no reason to think that any kind of subliminal messaging will be tried. For instance, there are several...... you know, I could really use a Coke right now. Oh yes, that crisp, refreshing taste...... key laws and basic controls that will prevent that from happening.

author: TERRA Operative
author_rank: Super Contributor
timestamp: January 06, 2019, 09:55:07 am
content: Cisco Teams and their other associated apps can do this to detect when you are in your office etc and switch modes and activate/deactivate features and settings automatically.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 06, 2019, 04:40:34 pm
content: What frequency range exactly are they talking about?Wondering how they can ever make sure that it would work on a variety of devices. It may work on some specific devices that have enough audio bandwidth all the way to the speakers not to attenuate frequencies above ~20KHz too much and conversely have microphones that are sensitive enough at those frequencies to capture some usable signal, but it would certainly not work in the general case.Since all modern devices use digital audio, making use of ultrasounds would also imply the standard sampling frequency of 96kHz probably or above (the standard 44.1kHz or 48kHz aren't high enough to get anything really usable above 20kHz, it would be aliased and thus become audible...) As for capturing, I don't know of any phone or tablet that captures sound from their microphones at above 48kHz.A lot of the internal speakers of TV sets are crap (let alone those in phones and tablets) and unable to emit any amount of usable acoustic energy at ultrasonic frequencies (again there may be unwanted exceptions but you couldn't rely on that), and nowadays a lot, if not most mobile phones microphones are MEMS-based, with rather wildly varying characteristics from model to model. MEMS microphones usually (but not all) have a frequency response usable above 20kHz (but pretty much never documented), but again you'd be playing with just odds and again, there is the sampling rate issue and the analog front-end as well (whether it's embedded in the microphone itself or not).Would be interested in getting more technical info on this "technology", as it "sounds" fishy at first thought.

author: madires
author_rank: Super Contributor
timestamp: January 06, 2019, 04:51:08 pm
content: Talking Behind Your Back (33c3):

author: JPortici
author_rank: Super Contributor
timestamp: January 09, 2019, 01:12:47 pm
content: altough i did read on how certain TVs communicate with certain phones during commercial to suggest particular ads

author: Rerouter
author_rank: Super Contributor
timestamp: January 09, 2019, 01:29:18 pm
content: At a guess, something in the 14KHz and higher range would do just fine, with a very short duration you cannot tell the direction of the noise. and if your just blurting out a UID or similar, well there is not much data.I recall this form of ad tracking already being in place with some dodgy gaming apps, they listen for a sound signature in ads to report who was present for it. but no idea how widespread it is, but I can understand it from a technical perspective.

author: Halcyon
author_rank: Unknown
timestamp: January 11, 2019, 01:05:13 pm
content: This sort of thing isn't really new.Consumer products have exploited this kind of "out of band" information transfer for quite some time. Just look at something like the first generation Google Chromecast (released in 2013), it transmits audio via the TV/display for the "casting" device to listen to and authenticate (if you don't want to punch in a PIN).

author: MrMobodies
author_rank: Super Contributor
timestamp: January 13, 2019, 09:45:14 pm
content: Talking of inaudible sounds:What would the audiophools have to say about that if they could hear it.They claim to here a lot of things.

author: Barny
author_rank: Frequent Contributor
timestamp: January 15, 2019, 09:56:54 am
content: Thats the first real practicable usecase of the ultra sonic phone charger.Blast the Phone 24/7 with ultra sonic sound to prevent spy signals.(And hope the electronic components within the phone don't rattle loose.)