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Ultrasonic Payments

charliegerard.dev

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Re: Ultrasonic Payments

#41

Post by kevin_nisbet »

hgomersall wrote: post #39
jjeaff wrote: post #25

Earlier quoted context omitted.

I disagree that there are better ways to transmit data p2p in most devices. Even the smoothest of setups for things like iot devices usually require a Bluetooth connection with a passcode or a connection to a lone wifi signal after which you need to switch back. Using sound would be a perfect way to setup iot speakers or really anything close by. Instead of having to activate Bluetooth pairing and find the sometimes…

The key exchange problem doesn't go away because you're using ultrasound.

Correct, although it's not that it goes away, more of a it has different properties. The short time I worked in the IOT space, I was a big proponent of exploring an option like this for bootstrapping the WIFI connection in a device that otherwise had just a button or two.

The basic problem is, the wifi password needs to be shared with a device without an interface.

The traditional method at the time was the device boots with an unsecured wireless network. And an app on the phone is used to connect to the network, and share the wifi password, and then rendezvous on the wifi network to continue provisioning. I think there are some protocols for this that I don't fully remember now. There's lots to consider in this method, such as can someone sniff the transfer, how is that protected, what is the range to pick up, etc. Can someone trick the app into connecting to some other device, etc, etc. If you put mitigations in, how can those be countered.

With sound / ultrasound based provisioning (the device I'm talking about already had a microphone and speaker), the range is more limited to who can hear the device. The signal strength is much weaker, an eavesdropper might need to be in the same room. This might allow weaknesses in the overall model of key exchange to be less of a concern, as the properties change to something a lot harder to intercept.

Re: Ultrasonic Payments

#43

Post by dancsi »

This reminds me of how the student meal subsidies are implemented in Slovenia, and in my opinion it was quite unwieldy. You call a phone number and place your phone's earpiece on another device with a microphone. Then, some personal data is transmitted using (ultra?)sound. I remember it being quite unreliable, but that might be down to using the telephone network as the data carrier.

Re: Ultrasonic Payments

#44

Post by indiantinker »

Very cool idea! I once worked on something similar [1], but even more low-tech, for CHI student design contest[2](we won). The idea was to do it over an IVR call and without a necessity of smartphones. The users were older people in India who find it hard to use and trust payments. I would love to work on this. I feel, we need more projects in offline and digitally accessible payments. On one end we have Apple Pay later and the other hand we have cash.

[1] http://rohitg.in/portfolio/works/paisa.html

[2] http://st.sigchi.org/publications/toc/chi-2017-ea.html

Re: Ultrasonic Payments

#45

Post by nonrandomstring »

muglug wrote: post #11

Reminds me of Clinkle ( https://en.wikipedia.org/wiki/Clinkle ) which hoped to use sound to transmit payments.

Also Chirp. I wrote an error correcting modem for them. Getting a simplex packet from A to B is the easy part. But any kind of bidirectional protocol (say for flow control) falls apart in an acoustic medium because duplex operations are thwarted by echo and phase. It's a long time since I played with the idea but I reckon you could do a lot more now with phones that have mic arrays and enough CPU power to do more serious DSP.

Re: Ultrasonic Payments

#46

Post by tut-urut-utut »

dancsi wrote: post #43

This reminds me of how the student meal subsidies are implemented in Slovenia, and in my opinion it was quite unwieldy. You call a phone number and place your phone's earpiece on another device with a microphone. Then, some personal data is transmitted using (ultra?)sound. I remember it being quite unreliable, but that might be down to using the telephone network as the data carrier.

I remember back in the time, during the eighties, one of the radio stations broadcasted ZX-Spectrum games over the air. You would record that noise to a tape, and later you could load to your ZX and play. It worked remarkably good.

Re: Ultrasonic Payments

#47

Post by jhugo »

shepherdjerred wrote: post #40
mercurywells wrote: post #34

Earlier quoted context omitted.

I have one as well, and I've noticed that area proximity detectors (in hallways used to detect presence/motion) do get picked up and come through as loud pops.

How loud? These are audible to me without an implant (unless some are audible and some are inaudible)

You might be hearing a relay, which is itself switched by the proximity sensor.

Re: Ultrasonic Payments

#48

Post by noobermin »

I will say this is a cool project. However, the implementation of the idea in reality is even worse than NFC. While NFC is useful in many contexts, it then requires you to put a faraday cage around your card and manually turn on or off the NFC to not get your money stolen, and even then can be circumvented. Even further relaxing the distance constraints even makes it even easier to steal money. I'd imagine a lot of the engineering would go into making it safe (having some set up such that the US sounds vary to some degree...then may be even an authentication protocol..then...then...then...

The moment I saw the headline, I was incredulous. The actual project implementation in the article is a rather cool hack, so props to the author. I dread the day someone actually picks this up, assuming someone does actually choose to.

Re: Ultrasonic Payments

#49

Post by noobermin »

tut-urut-utut wrote: post #46
dancsi wrote: post #43

This reminds me of how the student meal subsidies are implemented in Slovenia, and in my opinion it was quite unwieldy. You call a phone number and place your phone's earpiece on another device with a microphone. Then, some personal data is transmitted using (ultra?)sound. I remember it being quite unreliable, but that might be down to using the telephone network as the data carrier.

I remember back in the time, during the eighties, one of the radio stations broadcasted ZX-Spectrum games over the air. You would record that noise to a tape, and later you could load to your ZX and play. It worked remarkably good.

Generally datasette formats were meant to work with the extremely lossy media of tape. Also, I'm not sure but telephone audio tends to be much more compressed compared to radio. That on top of the fact you are going from earpiece to mic with an air gap and the background noise, it's probably much much worse.

Re: Ultrasonic Payments

#50

Post by andi999 »

noobermin wrote: post #48

I will say this is a cool project. However, the implementation of the idea in reality is even worse than NFC. While NFC is useful in many contexts, it then requires you to put a faraday cage around your card and manually turn on or off the NFC to not get your money stolen, and even then can be circumvented. Even further relaxing the distance constraints even makes it even easier to steal money. I'd imagine a lot of t…

Cool technology, bad problem. I fully agree getting more distance is problematic. Not even in the sense of getting your data stolen, but also to allow pro active payment. I mean you want the customer to do an action (holding the card close to a device which shows the amount deducted) to conclusively agree to that payment. Not the cashier presses a button, and anybody too close pays for it.
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