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“Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

arstechnica.com

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Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#81

Post by colanderman »

blurbleblurble wrote: post #62
Cyph0n wrote: post #48

Earlier quoted context omitted.

> If a computer's audio drivers and audio hardware are set up to play back at standard CD/DVD sample rates (44KHz or 48KHz), then ultrasonics are not happening there, period. The same principle applies to inputs. What do you mean? All you need to do is sample the received audio at 44.1 kHz. Android at least has a low-level API which allows you to customize sampling rate.

According to Nyquist's work, you need a sample rate of 2f to represent a frequency f . So with 44.1 kHz you could only represent audio up to 22 kHz. There are kids who can hear at these frequencies.

And even then, you need a few kHz bandwidth for the low-pass filter. Those high frequencies are greatly attenuated.

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#82

Post by kapnobatairza »

This article is complete hogwash.

"Ultrasonic" beacons are like any other beacon technology, whether audible, inaudible, bluetooth based or otherwise.

All a beacon does is transmit an identifier or URL. It isn't and CAN'T track you. It is just a simple one-way broadcast that is saying "X is here". You need an application that knows to listen for beacons an knows how to translate the identifier of the beacon.

For example, if Starbucks is using a beacon and you go near it with your phone, your phone will do nothing with that beacon unless you have the Starbucks app that is looking for Starbucks beacons so the app knows when you are near a Starbucks.

There is nothing nefarious about this....

Ultrasonic is just another method to achieve the same result, although it seems like a bad way of doing it since it is fairly obvious when your app is "listening" on iOS.

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#83

Post by stcredzero »

Just because ultrasonics are inaudible doesn't necessarily mean they're harmless. Energy deposited into those little hairs in your cochlea is still energy. What does the research say about the impact of ultrasonics on hearing? I wouldn't be surprised if they're the same as any kind of sound, decibel per decibel. (They're easier to block out, being at a higher frequency.)

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#84

Post by wallacoloo »

IshKebab wrote: post #51
jonasvp wrote: post #22

Earlier quoted context omitted.

Poor dogs...

And humans. These things aren't really ultrasonic because phones and computers can't transmit ultrasound (why would they need to?).

This is something I was curious about. Sure, if you're doing serious audio editing and such, you might sample at e.g. 96 kHz, and I wouldn't be surprised if Android also allows that. But does this really not get band-limited at any point in the stack?

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#85

Post by mSparks »

bradyd wrote: post #54
mSparks wrote: post #6

anyone know of an app that can detect these signals? Maybe decode them. easiest way to block them is to know they are there in the first place. i am suspicious that occasionally my laptop makes high pitch noise correlated to mouse movements when its running windows 10. edit:Thinking about it. seems possible that might actually be facebook. never installed their phone app untill i had android 6 because it wants mic pe…

The sound is probably coming from the LCD screen. https://news.ycombinator.com/item?id=8862689

I discounted that at the time by playing a muted YouTube video and using keyboard shortcut forward back.

It only altered in any meaningful way to trackpad movements and clicks.

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#86

Post by JonSchneider »

AlphaSite wrote: post #42
AlphaWeaver wrote: post #29

Earlier quoted context omitted.

On iOS there is a prominent red banner informing an app is listening if it is listening in the background.

Also, if I'm not mistaken, only 1 app can listen at a time.

On iOS multiple apps can listen at one time. On Android only one app can listen at a time.

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#87

Post by eridius »

Analemma_ wrote: post #68
pklausler wrote: post #66

Earlier quoted context omitted.

Whoa, wait a sec there with your example. How would a reasonable person not want to be an organ donor??

There is a theory that organ donors get worse medical attention and have higher mortality rates in hospitals. From what I've seen it doesn't hold up well against the evidence, but it's still within the bounds of what I'd call "reasonable disagreement".

That doesn't sound reasonable at all. That theory hinges on the idea that doctors would prioritize getting organs over actually saving people's lives, which would be a truly horrific violation of the hippocratic oath.

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#88

Post by RIMR »

pklausler wrote: post #72
rfrank wrote: post #67

Earlier quoted context omitted.

Religious reasons, family not wanting that to happen, etc.

If your religion forbids saving or improving the lives of others with organs you're done with, please consider alternatives.

If one facet of someone's faith is enough for you to dismiss their entire belief system, you clearly don't even try to understand others' differences to yourself...

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#89

Post by pklausler »

RIMR wrote: post #88
pklausler wrote: post #72

Earlier quoted context omitted.

If your religion forbids saving or improving the lives of others with organs you're done with, please consider alternatives.

If one facet of someone's faith is enough for you to dismiss their entire belief system, you clearly don't even try to understand others' differences to yourself...

Oh, I try. But in the case of organ donation, I simply fail to understand the reasoning. If you're dead, why not save a life, renew sight, or otherwise greatly improve the life of another? Are there people who think that organ donation would hurt them in an afterlife? We, at least in the first world, live in societies with freedom of conscience and belief, so people should at least think through the consequences of their choices on others. (And on themselves; if there's an afterlife, do you really want to risk being judged on the basis of having chosen to deny a chance at health and wellbeing to another person?)

Re: “Ultrasonic cross-device tracking” embeds inaudible tones in advertisements

#90

Post by RIMR »

kapnobatairza wrote: post #82

This article is complete hogwash. "Ultrasonic" beacons are like any other beacon technology, whether audible, inaudible, bluetooth based or otherwise. All a beacon does is transmit an identifier or URL. It isn't and CAN'T track you. It is just a simple one-way broadcast that is saying "X is here". You need an application that knows to listen for beacons an knows how to translate the identifier of the beacon. For exam…

>All a beacon does is transmit an identifier or URL. It isn't and CAN'T track you.

If my devices are transmitting identifying beacons, then they absolutely ARE tracking me. What exactly do you think that "identifier" is?

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