
Beware of ads that use inaudible sound to link your phone, TV, tablet, and PC - ivank
http://arstechnica.com/tech-policy/2015/11/beware-of-ads-that-use-inaudible-sound-to-link-your-phone-tv-tablet-and-pc/?
======
JoshTriplett
One of many reasons I find it amazing that applications ask for permission to
the microphone when they don't have a good reason.

The latest Netflix update on Android asks for microphone permissions, saying
that in the future they'll offer a way to call Netflix support from within the
app. _No_ , that's not a good reason; I have a phone for that. I've
specifically avoided that upgrade; I'm hoping that my Nexus gets the upgrade
to M before then, so that I can upgrade Netflix but deny it access to the
microphone.

~~~
danepowell
This is why on-demand permissions are one of the best features of Android 6.0.
Don't want Netflix to access your microphone? No problem--don't let it.

~~~
maccard
And remember. iOS has had this since its inception

~~~
JohnTHaller
No, it didn't. iOS originally gave apps access to just about everything except
background execution without any warning. At the time Android had the superior
permissions model, with each app telling you what it needed at install and you
being in control of whether or not you wanted to install it with that
information. Older iOS apps had access to your photos, your contacts, and
other stuff and could use it with no warning to you.

As a result of early privacy breaches, later releases of iOS added per-
function permissions on demand, leap-frogging Android in terms of permissions
functionality. Android has had some level of per-function permissions on
demand in the works since Android 4.4 -- and you could use it in unofficial
Android builds like CyanogenMod by turning off individual permissions for apps
-- but the feature only finally made it into official builds in Android 6.0.
It also got it properly in the API and manifest of apps as well so they can
ask permissions as they need them... like the Facebook app needing access to
your photos when you select to attach a photo to a post.

~~~
threeseed
Apple started adding location services permissions 5 years ago. Android 6.0
has only just been released.

Whichever way you look at it it's pretty unacceptable that it's taken so long
for Android to implement this.

~~~
yareally
> "Apple started adding location services permissions 5 years ago. Android 6.0
> has only just been released".

Location permissions have been in Android since the version 1.0 of the API.

[http://developer.android.com/reference/android/Manifest.perm...](http://developer.android.com/reference/android/Manifest.permission.html#ACCESS_FINE_LOCATION)

~~~
threeseed
But that is the permissions that only appear when you download the app from
the store.

I am talking about the API permissions e.g. "the dialog box that pops up
confirming you want to allow this app to read your location".

That is the point of this whole discussion right ?

------
ransom1538
I am happy this was brought up. I have been approached by companies to add in
"SDKs" of this sort. They usually offer to pay you per user. When you have
scale, these companies while the app is open can scan for other media they
need to link. I have witnessed iOS apps processing web ads, tv stations and
radio ads. The freakiest was watching the software understand a tv show was
playing, detect which show, then off a competing ad in the app.

It is quite amazing what a phone can absorb while sitting in a living room
with a loud tv blaring (which is most of america).

See more: [https://www.audiblemagic.com/](https://www.audiblemagic.com/)
(Edit, you will see "Facebook" as one of their customers.....)

~~~
eclipxe
Facebook has a feature that allows to detect what you're watching or listening
to when you post a status update. No secret or conspiracy there.

~~~
a3n
OK, but how do they present it? As a benefit to users? Or as a benefit to
advertisers?

------
jnevill
This just doesn't seem feasible in the real world. Sending out high frequency
sound from a device is one thing, but having the other devices actively
listening for the sound, is quite a feat. It's mentioned inside a block of
text in a quoteblock in the article: "The inaudible code is recognized and
received on the other smart device by the software development kit installed
on it.". From where does one get this SDK installed on their device with
enough permissions to actively listen for its counterpart ad? There's just too
many points of failure for this to be a real threat, or a real marketing tool
for that matter.

~~~
tedmiston
Full disclosure: I work for an audio beacon startup (in bio).

You're correct about microphone permissions related to the SDK. On iOS, this
means displaying the top colored bar when you're using the microphone too...
IMHO it's not something you can just turn on and not realize it's being used.

We use our listening tech at concerts and event to distribute triggered
content and messages from the speaker infrastructure to attendees' phones (ex.
"this drink line is long, go to the other one", "here's a free song from the
artist on stage right now", "<sponsor> is giving away a free thing", etc.)

~~~
geon
Why not just use bluetooth beacons for that?

~~~
tedmiston
The strongest answer is that bluetooth beacons don't work well in huge
infrastructure. Sometimes you don't have a place for them to go or they get
stolen. Also it's free to use the speaker infrastructure, but outfitting and
managing hundreds of beacons is not cheap. Some of our clients have switched
to audio beacons for similar reasons.

The Brooklyn Museum did a nice writeup of why bluetooth beacons at scale
didn't work for them.

[https://www.brooklynmuseum.org/community/blogosphere/2015/02...](https://www.brooklynmuseum.org/community/blogosphere/2015/02/04/the-
realities-of-installing-ibeacon-to-scale/)

~~~
rasz_pl
Yes, BT beacons are not cheap when you buy $100 ones from a startup, also
whole article was TLDR:'if only we could but a can of spray paint and change
color of beacons, but we cant so oh well'

~~~
makomk
Those beacons have some kind of rubberized case; you can't really spray-paint
that. (Also, last I heard the cheaper beacons still weren't terribly cheap and
had awful battery life.)

~~~
ryoshu
HM-10s are a couple bucks in bulk, but managing a large deploy is still
difficult.

------
beloch
Well, there's one more reason to block online ads and avoid watching TV. It's
as if the people developing this tech _want_ to be put out of business.

~~~
TeMPOraL
They don't care. They're swimming in money _now_.

------
pinkunicorn
Jokes on you, my TV is 15 years old and I've a Nokia 1100.

~~~
grecy
Even better, I own neither :)

~~~
benihana
Oh my god, that is so interesting and different. You must be a really unique
and free thinking person to not own a TV or a phone. I bet you have really
interesting opinions!

~~~
beedogs
Oh hey, someone from Reddit decided to comment here instead.

~~~
oh_sigh
I love how you combat a shit reply with a shit reply of your own. As if Reddit
is a single entity and not a collection of somewhat independent communities

------
sehugg
@jimfenton recorded some audio from Cartoon Network in an attempt to find
these beacons: [http://altmode.org/2015/11/13/searching-for-ultrasonic-
beaco...](http://altmode.org/2015/11/13/searching-for-ultrasonic-beacons/)

FSK at 17.5 and 18.5 kHZ is one possibility, but wasn't detected in this
experiment.

~~~
simoncion
To nit-pick: Anything under 20kHZ isn't ultrasonic. :) (Not that either _you_
or the blog author called this high-frequency signalling "ultrasound", but it
_does_ appear to be what people are calling it. :/ )

~~~
digi_owl
But it seems to fall into the range used by those "mosquito" devices. Meaning
it is on the edge of what most humans can hear at young age, and lost with
age.

~~~
simoncion
No doubt. It's still not ultrasonic. :)

------
coldnebo
This is fantastic news. The marketers have given us an excellent key by which
to block ads and distinguish ads from content! Nice!

~~~
Lagged2Death
It's a lovely sentiment, but if this actually takes off, the content-makers
will eventually join in, inserting identical or similar beacons directly into
TV/movies etc. for similar reasons.

------
kordless
Listen up. Nothing in this reality, currently, is particularly secure. Use
anything outside your own brain at your own risk. Seriously.

Things are likely to improve, but it's going to take time.

~~~
bbcbasic
Yep... these are the good old days when you can think stuff and no one else
knows about it. Enjoy it while it lasts little brother.

~~~
kordless
A multi-tenant only view will lead to obvious outcomes for single tenants. My
sense is that this is the nature of things, to vacillate between single-tenant
and multi-tenant models. A pure multi-tenant model, which is also highly
secure, is probably little different from this reality. It's exceedingly
difficult to make things vanish here.

------
twerkmonsta
Pretty interesting that SilverPush has a product for "Real time TV Ad
Analytics" called PRISM [1].

[1] [http://www.silverpush.co/](http://www.silverpush.co/)

------
mindslight
If untrusted code has this kind of access to your microphone, you have much
bigger problems.

~~~
angelbob
And/or an Android phone, apparently.

~~~
mindslight
If Android apps can use the microphone without a clear indication,
_especially_ in the background, then that is a serious security bug in Android
and should be reported with that context and _fixed_ , rather than weird
nobody's-fault alarmism.

~~~
pilsetnieks
That's what you get with a permission model of "hey, if you don't like that
this app asks for every permission known to man, just don't use it!"

~~~
mindslight
Well no. I purposely avoided getting into that territory, even though I have
strong feelings probably similar to yours.

Even with the take-it-or-leave-it faux-contract of adhesion permission model,
there should be a visual indication when an app is using the microphone.
Background microphone (not as a result of a directly preceding user intent)
should be a separate additional permission, and probably shouldn't be exempted
from having a visual notification with an easy way to mute the passive
listening.

------
givinguflac
Most of this could probably be mitigated within the home by installing rodent
deterrent systems that emit high frequency (inaudible) noise. It would like
drown out the lower signal level of this type of signal. S/N ratio for the
win.

------
mercora
I noticed hearing strange high pitched background noise i normally tend to
hear from power supplies but only at certain advertising spots. I thought the
TV might be about to fail, it may is, but this sounds plausible too.

~~~
Eldarrion
I do believe they claim that they use _inaudible_ sounds, i.e. something
outside a human's hearing range. Sorry, but chances are your TV is going wonky
on you.

~~~
floatrock
Inaudible is a fuzzy line.

I remember growing up always hearing around the house the hum of the CRT TV
when my parents would turn the cablebox off and not realize they left the tv
running. Parents never heard anything. You start to lose hearing at upper
frequencies around as early as in your 30's... when I talk to my friends about
this, a surprising number of them (even the non-techies) remember this barely-
audible-CRT-hum noise pollution phenomenon.

The upper range of human hearing is about 20khz. From a design and
manufacturing-costs point of view, it doesn't make sense to design a speaker
that can reproduce sounds much above human hearing. If you're gonna be
optimizing the speaker cone for _anything_ , you're probably gonna set an
upper bound around the upper range of human hearing, _maaaybe_ go a little bit
above if you're high quality and want to reproduce everything.

So, your average TV speaker is probably going to reproduce some sounds above
the upper range of human hearing, but not too far above. The higher into the
inaudible range you design your beacon, the more likely it's _not_ going to
work, because not enough TV's are going to be able to reproduce it and your
system becomes unreliable.

If I was building such a beacon, there's a good argument to be made to target
your signal tone at or slightly _below_ the upper range of human hearing,
making it audible.

So (unless I don't know some detail about speaker design and there's a class
of speakers that aren't generally limited at around 20khz, in which case
please share) I actually think it's likely they're using _almost_ -inaudible
tones. In which case OP should smile knowing 1) he's not yet losing his upper
range of hearing, and 2) he's now experiencing the new generation of the
barely-audible-CRT-hum noise pollution phenomenon.

\-------

[edit: yep, looks like that's exactly what they're doing. Check out this short
blog post from a comment further down about a guy spectograph-hunting for
these:

[http://altmode.org/2015/11/13/searching-for-ultrasonic-
beaco...](http://altmode.org/2015/11/13/searching-for-ultrasonic-beacons/)

The bottom of the post links to a patent for this tech. "It refers to the
insertion of frequency-shift keying modulated data at 17.5 and 18.5 kHz."
Boom. Right in the fuzzy area of the limits of human hearing. ]

~~~
caf
With CRTs I believe it's the flyback transformer frequency you can hear.

~~~
gvb
Correct.

262.5 lines/frame * 60 frames/sec = 15750 Hz.

Ref:
[http://www.infocellar.com/television/scanning.htm](http://www.infocellar.com/television/scanning.htm)

------
grayfox
This is ludacris. Where is this currently being applied, if anywhere in the
general wild?

~~~
tempestn
Ludacris:
[http://thekoalition.com/images/2013/05/Ludacris.jpg](http://thekoalition.com/images/2013/05/Ludacris.jpg)

Ludicrous:
[http://dictionary.reference.com/browse/ludicrous](http://dictionary.reference.com/browse/ludicrous)

(Sorry, normally I wouldn't point out a spelling mistake, but hopefully this
one is amusing as well as informative.)

~~~
Jack000
there's no proof either way, I choose to believe that Ludacris browses hn
under a pseudonym

~~~
avn2109
Agreed. Luda also has > 100 karma and a public key in his profile link.

~~~
nickpsecurity
He pretended to run a hacking crew in Gamer. Had dreams of what life would be
like as a real one. That's where his transformation and stealthy visits on HN
began.

------
dennyabraham
The microphone permission is one of the most pernicious. What might not be
immediately clear to people is that a number of ambient sounds and almost all
ambient music emit steganographic location data. Furthermore, additional
metadata is encoded in other data that your phone's sensor package can read if
it turns out to be on.

------
Dowwie
I think this requires more attention, across all media

 _Submit your comments to the FTC_
[https://ftcpublic.commentworks.com/ftc/crossdeviceworkshop/](https://ftcpublic.commentworks.com/ftc/crossdeviceworkshop/)

for more information about the upcoming event and to access comments:
[https://www.ftc.gov/news-events/events-
calendar/2015/11/cros...](https://www.ftc.gov/news-events/events-
calendar/2015/11/cross-device-tracking)

~~~
dang
"Please don't use uppercase for emphasis. If you want to emphasize a word or
phrase, put asterisks around it and it will get italicized."

[https://news.ycombinator.com/newsguidelines.html](https://news.ycombinator.com/newsguidelines.html)

------
meowface
While this is very invasive, you have to admit as an engineer that it is
_cool_.

~~~
floatrock
yes, but, obligatory xkcd: [https://xkcd.com/1520/](https://xkcd.com/1520/)

------
chinathrow
What a fucked up world we live in. If you work in advertising and if you work
on such systems: be ashamed. Very much ashamed.

------
Daishiman
I really, really hope this is made illegal.

It borders on parody what level of dystopic thinking made this.

~~~
x1798DE
Even if this _is_ a real threat vector, I imagine that in the time it would
take to make this illegal and try and prosecute even one person, it will have
been dealt with naturally by device manufacturers. Already this would be easy
to defend against with any devices with properly granular permissioning.
Meanwhile, anyone this far out on the bleeding edge of trying to track you
will have a dozen other fingerprinting mechanisms rolled out by then and will
have no problem dropping this ludicrous attack.

Legislation is _rarely_ the right tool.

~~~
ubernostrum
The legal framework is actually already mostly in place due to laws detailing
the necessary consent to record a telephone conversation. So it might not take
much to extend that concept to applications on a phone other than the actual
phone app.

~~~
lotu
It would be hard to argue the wiretap laws apply to recording ultrasonic
sounds extracting data from them. Honestly their isn't even the need for the
device to store the audio, much less send it off the device.

~~~
ubernostrum
Microphone access, especially if it's always-on to listen for the cue, is
going to end up recording conversations, and those conversations will almost
certainly involve people who are not the phone's owner and so could not have
consented to having that phone record them.

(also there's the general problem of devices "helpfully" listening all the
time for magic phrases like "Hey Siri" or "OK Google")

~~~
lotu
Having microphone access dosent equal illegal wiretapping, sure it might be a
prerequisite. Yet you need to prove more than that the app _could_ illegaly
wiretap you if the developer wanted to do that to use the law to go after
these apps

------
wahsd
Why do I get the sense that the advertising industry has a death wish. It's
like there is periodically some secret meeting somewhere where they hatch
plans for how they can get even the littlest old lady to hate them so much
that they run ad blockers on everything and everywhere.

BTW, I have always wondered why there are seemingly no solutions for blocking
ads on a regular old TV, even if it's just a matter of muting the ads and then
unmuting for the show/movie.

I remember I used to have a TV that you could easily set a timer on a channel
when a commercial block started and then flip through the other channels and
once the timer was up it would automatically switch back to the channel with
the show or movie you were wanting to watch.

I get that that's not technologically very advanced, but the point is that
that was many years ago and it's really not gotten better and even such simple
solutions have disappeared and now we are left with highly sophisticated
systems that will not allow for easy adding of ad blockers.

~~~
a3n
Now that TVs are connected, TV manufacturers get to have a piece of the ad
pie. That would make them as reluctant as Google to make it easy to kill ads.

------
voltagex_
Can someone get me a copy of the APK for
[https://play.google.com/store/apps/details?id=com.teleca.sam...](https://play.google.com/store/apps/details?id=com.teleca.sam.engine&hl=en)?
It's likely that this has the SilverPush SDK.

~~~
brbsix
[https://tusfiles.net/3d5ea3kw8nky](https://tusfiles.net/3d5ea3kw8nky)

A very cursory look seems to indicate the microphone permission is used by
Gracenote
([https://developer.gracenote.com/](https://developer.gracenote.com/)) music
recognition SDK.

~~~
voltagex_
Damn, looks like I missed the mark on that one.

I was basing my assumptions on
[http://stackoverflow.com/questions/32432785/i-have-
updated-a...](http://stackoverflow.com/questions/32432785/i-have-updated-
android-api-to-23-and-there-is-no-error-in-any-xml-file-but-when) which shows
that the package we're looking for is com.silverpush.sdk.

The developer who asked that question works for the company who released that
app.

The app description also says "Download MI Mobile and activate today, then
just keep your phone with you throughout the day (including while you watch
TV) with MI Mobile running in the background." which made me suspicious.

~~~
brbsix
Below is just a little bit of relevant source from the demo app. As you can
see it certainly appears to be listening for audio beacons. Now the
interesting part would be to find an easy way to determine which other apps
are using this.

    
    
        void a(String s1, String s2, String s3, String s4)
        {
            i();
            p.setVisibility(8);
            w.setVisibility(8);
            s.setVisibility(0);
            s2 = Uri.decode(Uri.encode(s2));
            if ("video".equals(s4.toLowerCase()))
            {
                s2 = new StringBuilder();
                s2.append(s3);
                t.loadDataWithBaseURL("file:///android_asset/", s2.toString(), "text/html", "utf-8", null);
                q.setText("Demo : Audio Beacon Detected");
                r.setText(s1);
                q.setText("Found a match !!");
                return;
            } else
            {
                StringBuilder stringbuilder = new StringBuilder();
                stringbuilder.append("<html><body style='margin:0;padding:0;background-color:black;'><a href='").append(s2).append("' ><img src='").append(s3).append("' height=250 style='margin:0 auto;display:block;' /></a></body></html>");
                t.loadDataWithBaseURL("file:///android_asset/", stringbuilder.toString(), "text/html", "utf-8", null);
                s3 = new StringBuilder();
                s3.append("<html><body style='margin:0;padding:0;background-color:black;'><a href='").append(s2).append("' ><img src='").append(s4).append("' height=50 style='margin:0 auto;display:block;' /></a></body></html>");
                u.loadDataWithBaseURL("file:///android_asset/", s3.toString(), "text/html", "utf-8", null);
                q.setText("Demo : Audio Beacon Detected");
                r.setText(s1);
                q.setText("Found a match !!");
                return;
            }
        }

~~~
voltagex_
The package name is obfuscated, correct?

~~~
brbsix
I'm not sure what you're referring to. An aapt dump shows the package name as
'SilverPush Demo App' (version 1.0.3). It appears the same in the app drawer.
If you mean the class files, then yes they are obfuscated. ProGuard (or
something like it) was used to obfuscate the Java, but that is pretty par for
the course.

It is connecting to a few servers:

    
    
      http://54.243.149.109:8040/register
      http://54.243.149.109:8086/receiver
      http://ad-x.co.uk/API/click/Hungind45789jo/am554ec53dd8d021/NET/aff_sub/SilverPush?subid=aff_sub2&ord=[random]
      http://mobext.com
      http://silverpush.com
    

So presumably these (along with other mobile ad networks) can be blocked via
hosts file or MinMinGuard (Xposed). Not great, but probably a good course of
action for now.

~~~
voltagex_
More like we can't scan APKs for particular API calls because it looks like a
call to a.a.b.a() internally. I guess package name was the incorrect term to
use.

~~~
brbsix
Oh right, yes exactly... Though some of the "Anti-virus" apps are pretty good
about identifying ad networks, so I suspect it's not a big problem to detect
one way or another. Of course SilverPush could get pretty nefarious if they
wanted to, but if that demo app is a proper exhibition of their products then
I don't think we should be very afraid :)

------
tdaltonc
This reminds me of chromecast's ultrasonic guest mode.

[https://gigaom.com/2014/12/11/chromecast-gets-guest-mode-
tha...](https://gigaom.com/2014/12/11/chromecast-gets-guest-mode-thanks-to-
cool-ultrasonic-tech/)

~~~
digi_owl
Never mind a certain computer security claim regarding a airgapped computer
leaking data.

~~~
icelancer
What ever came of BadBIOS? Was it actually legitimate?

~~~
fabulist
The only people who know are Dragos Ruiu, his associates, and possibly some
incredibly talented (if strangely sadistic) malware authors.

------
mirimir
Wow, I'm impressed! But I'm also prepared. I _always_ mute during TV ads, to
reduce brain pollution. None of my boxes have microphones, and most have no
audio. And I don't use smartphones.

~~~
trebor
Combine your techniques with adblocker software, and anyone's pretty much set.
I do have systems with mic/speakers, but I block ads. And I don't own a smart
TV, just a cheapo dumb one w/o an internet connection.

~~~
mirimir
Yes, I forgot to mention browser security. I use private browsing mode, delete
all cookies at browser shutdown, block ads and nonessential scripts, use
Privacy Badger, and have disabled many insecure and useless features.

But I don't (yet) work in a Faraday cage ;)

------
peteretep
It's a sad day when Apple are the company I trust most with my privacy.

~~~
jakejake
I feel like Apple actually does offer good privacy features on their devices.
Of course watching one's parents just click OK on everything to make the alert
dialog go away, makes you realize that the device makers can only do so much.

------
gregwtmtno
It sounds crazy, but I noticed my phone was emitting a quiet, high-pitched
buzzing sound when I had 2048 open the other day. I wonder if this is what I
was noticing.

~~~
melloclello
Which 2048 app?

~~~
danneu
2048+ Plus Pro Free HD

~~~
ceejayoz
Sounds like the name for a Samsung phone.

~~~
ArekDymalski
Nah, not enough Galaxy in there.

------
lips
So a low-level low-pass filter would throw a nice wrench in this, right? I
wouldn't really mind having most of my devices limited to 20Khz.

~~~
jacquesm
Depending on your age you could get away with a lot lower than that and not
miss a thing.

------
alejohausner
This is provocative and very tacky, but I'm sure that advertisers can cross
correlate many clues about our web behavior, and already have a pretty good
idea about our habits and responses to ads. I don't see a real need for this
sort of creepy intrusiveness.

~~~
fabulist
Heuristics are very well and all, but certainty is another matter entirely.

------
alexisnorman
Kind of like a reverse Portable People Meter:
[https://en.wikipedia.org/wiki/Nielsen_Audio#Portable_People_...](https://en.wikipedia.org/wiki/Nielsen_Audio#Portable_People_Meter)

------
loginusername
"... and there is no option to opt-out of this form of cross-device tracking."

Does it work with Javascript disabled?

Does it work with text-only browsers?

How about netcat?

Do I have to get a "smartphone" to make this work?

------
owlish
Could this not also be used in the near future by, say, the LinkedIn app to
identify "People You May Know"?

------
incepted
This sounds a lot like some scifi unwarranted fear mongering article.

Is there any evidence that such a thing exists?

~~~
lolc
I was wondering the same thing. Samples or it didn't happen :-)

------
stuaxo
This, is beyond creepy straight out and out surveillance, and they need to
piss right off.

------
giaour
Suddenly a blackphone seems like an excellent investment...

------
teaneedz
We need a published list of companies using this tech.

~~~
ericflo
Would chirp.io be placed on this list?

------
nommm-nommm
This gives new meaning to subliminal advertising.

------
upofadown
TLDR: There is some malware out in the wild called SilverPush that does
interesting new bad things.

------
privacy101
Invisible light should probably also be kept in mind, although probably not as
problematic.

------
peter303
People are so paronoid these days. Our Internet of Things ganging up to
control us!

~~~
GhotiFish
normally i'd say that it's not really paranoid if they're really out to get
you...

but the attack vector described here. It requires too many devices actively
compromised for any usable data to be gleaned. Manufacturers are somewhat
sensitive to users demanding to control their devices peripherals.
Microphones, webcams, cameras, speakers. It's not perfect, but there's enough
moving parts here to make this kind of tracking seem bonkers.

For it to work, the person they have target will have blindly agreed to so
many things that they have all the information they want on them anyway.

~~~
nightpool
"blindly agreed to so many things"

you mean one permission prompt, on one app they may have downloaded years ago?

everything else is just the advertisers including high-frequency beacons in
their ad spots—it doesn't require any knowledge or cooperation of any of the
intermediary steps.

------
ericflo
This is really cool--it's essentially an audio QR code--and I think could
improve the user experience across a number of apps.

~~~
danso
Except with a QR code, I have to physically turn on my camera and point it to
the QR code, i.e. I have to _intend_ to process the QR code. Inaudible audio
seems to be something that would not require user intention.

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ericflo
That's what I think is so cool about it -- half the issue with QR codes is
that you have to open an app, point a camera at it, focus, and take a picture.
With this technology, you don't have to do any of those things. Nor do you
have to get on the same wifi, figure out how to bluetooth pair, or anything
else like that.

