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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

#121

Post by kimburgess »

rocky1138 wrote: post #56
Cyph0n wrote: post #49

I'm working on an app that passively picks up ultrasonic tones generated by SilverPush and sends out garbled data. The biggest issue with blanket interference across the entire ultrasonic band is that there are some legitimate uses that don't involve cross-device tracking. That's why we need to address this issue by selectively interfering with only known tracking schemes.

Can you elaborate on which legitimate uses you had in mind?

Anything that requires the ability to detect if it's in the same physical space as another device / item of interest.

Some common examples are:

* guest mode discovery on a Chromecast

* pairing to videoconference system (both Cisco and Polycom do this in their current gen devices), building control, wireless presentation system etc

* a means for transmitting a 2FA code from a personal device for auth / payments

* micro-location service - particularly for temporary events or spaces where BLE is not possible (e.g. embedded in FOH audio at different stages at a music festival)

* proximity based peer discovery for mobile games

You'd be surprised at how common a technique it is. I regularly face issues with environments that have had enough different devices all attempting to use some form of ultrasonic pairing / localisation etc that there's issues with interference.

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

#123

Post by sandworm101 »

B1FF_PSUVM wrote: post #120
sandworm101 wrote: post #73

Earlier quoted context omitted.

>> How would a reasonable person not want to be an organ donor?? Because I have fundamental issues with the economics of organ donation. I do not want my organs used in million-dollar surgeries to save elderly rich people. I would much rather that money be spent more efficiently on younger/poorer people where it can save more lives. How many flu shots could be purchased for the cost of one heart transplant? I cannot…

Fifty years ago, Larry Niven had some "moral tale" SF stories where the demand for transplant organs led to capital punishment for traffic violations. Also, technically there is no difference between cannibalism and organ transplants - ingesting the flesh of others of your species to save your life.

Except that some organ donation doesn't involve doing damage to the donor. Blood/marrow donations are different than 'solid organ' donation. A blood donation can save a life very cheaply and the recipient will live normally, without the lifelong costs/complications of carrying a donated solid organ.

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

#124

Post by prodigal_erik »

eridius wrote: post #87
Analemma_ wrote: post #68

Earlier quoted context omitted.

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.

I don't actually see anything in the Oath that requires prioritizing your own patient to the detriment of any number of other sick people.

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

#125

Post by eridius »

prodigal_erik wrote: post #124
eridius wrote: post #87

Earlier quoted context omitted.

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.

I don't actually see anything in the Oath that requires prioritizing your own patient to the detriment of any number of other sick people.

Perhaps a better way to say it is that it would be a very serious ethical violation.

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

#126

Post by ethbro »

codezero wrote: post #44
Lagged2Death wrote: post #41

Earlier quoted context omitted.

Since I don't hear a thing I'm not sure what is going on here. Click on the gem and the web page will play a "chirp," which is loud and beepy and not ultrasonic or secret at all. It's an analog modem type system, except probably way slower than 300 or even 110 baud. Everything old is new again, I guess. In any case, the point is: the Chirp system is distinct from the supposedly-possible secret systems the Ars story i…

Are there other devices besides the audio driver that could produce ultrasonic sounds when driven in a certain way?

I was curious about this too. My EE (particularly RF) studies didn't go far enough for me to chime in.

Is there power circuitry, etc that could likely (a) generate inaudible frequencies that overlap with mass-market microphone capability & (b) would be sufficiently controllable (albeit likely indirectly) for data transfer?

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

#127

Post by Lagged2Death »

gugagore wrote: post #47
Lagged2Death wrote: post #41

Earlier quoted context omitted.

Since I don't hear a thing I'm not sure what is going on here. Click on the gem and the web page will play a "chirp," which is loud and beepy and not ultrasonic or secret at all. It's an analog modem type system, except probably way slower than 300 or even 110 baud. Everything old is new again, I guess. In any case, the point is: the Chirp system is distinct from the supposedly-possible secret systems the Ars story i…

I think that most people (not teenagers) cannot hear past 15 kHz, especially with other sounds playing. This is reproducible at standard sampling rates you mention. Harmonics are integer multiples of frequencies. Harmonics of an ultrasonic signal are even more ultrasonic. If there's any aliasing, those harmonics might map back to audible frequencies. However, no matter how cheap a speaker is, no aliasing happens. Per…

Harmonics of an ultrasonic signal are even more ultrasonic.

You're right. I was thinking of resonances. Even in that case, I might be wrong.

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