
Kryptoradio – A Bitcoin data transmission system - mappum
http://kryptoradio.koodilehto.fi/
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johnyzee
This means parking meters, vending machines, laundromats, etc. can receive
bitcoin payments without an internet connection. That is actually really cool.

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sspiff
Well, only if the transmission is signed & trusted. Otherwise, an attacker
could just spoof a payment by transmitting a modified blockchain close to the
payment terminal.

Also, things like DVB tuners are not exactly cheap enough to be integrated
into many devices (though FM receivers, which may be used in the future, are).

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wyager
>Otherwise, an attacker could just spoof a payment by transmitting a modified
blockchain close to the payment terminal.

If the payment terminal used an SPV-like technology, the attacker would have
to have a tremendous amount of computing power. This attack is not feasible,
especially considering the relatively small reward of fooling an ATM or a
parking meter.

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Roritharr
Today. Parking Meters have a lifecycle of up to 25 years.

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kbaker
But since the meter would know the current difficulty level and with the auto-
adjustment of difficulty to the amount of hash power in the network, the meter
would be just as secure in 25 years as it is today even with incredible
advances in hash speeds.

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acd
Talking about that, Can anyone please transmit wikipedia via long wave radio?
It would be interesting in censor states. Hiding wikipedia in tv/movie
firmware would also be a possibility.

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mike_hearn
It just moves the thing that gets censored from the website itself to the
equipment needed to receive it.

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Tycho
Which is infinitely harder for authorities to control.

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bagosm
Thats all good and gimmicky but can you tell me: the 1-way connection offers
any value to anyone?

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servowire
With a DVB/Radio link to the network one could listen to transactions only to
their address. You could think of bitcoin operated gas stations, bitcoin
network-hubs in rural areas, micropayments to car-charging stations (all you
need is power and a cheap DVB receiver to listen to the address "beacon" for a
payment.

Now sending back transactions to the network is not covered, but can be done
by using SMS or a small radio link to a local node. A bitcoin transaction is
only about 64 bytes (!) so even a DTMF call or SMS should work fine.

A transaction send would look like this (normal TXid, in hex)

    
    
      a9d4599e15b53f3eb531608ddb31f48c695c3d0b3538a6bda871e8b34f2f430c
    

That would be

    
    
      76816061505687581068522220805344294890167166251289478281934616246172205973504 
    

in DTMF. Would take about 15 seconds to complete
([http://www.audiocheck.net/audiocheck_dtmf.php](http://www.audiocheck.net/audiocheck_dtmf.php))

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asdfaoeu
Why not just send the confirmation back by SMS?

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zouppen
The idea is that the payment receiver doesn't need to do it. The payee needs
to have some kind of uplink (like a mobile phone, amateur radio, or anything).

There are mobile payment applications already, but they are doing it using
centralized service and they need make deals with payment agents. With
Kryptoradio it is possible to receive payments without any extra middlemen.

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jtanner
Fascinating idea. In the areas that this would work, would it not be simpler
to just use a normal cell phones data connection or SMS?

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pronoiac
Say the blockchain's growing by a gigabyte a month.[1] I don't think SMS can
support that much, especially times so many devices. Using a tv signal is more
robust - you can support _millions_ of devices, and transient 3G network
failures will have less or no effect.

[1] I estimated. [http://blockchain.info/charts/blocks-
size](http://blockchain.info/charts/blocks-size)

~~~
nawitus
But the parking meter (etc.) doesn't need to handle the blockchain at all. It
could use the SMS to communicate with a shared parking meter bitcoin
transaction server. That said, broadcasting the blockchain is useful.

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zouppen
If you stick to centralized solution then that would work nice and might be
good enough. However Kryptoradio allows to do it by just listening incoming
transactions and blocks.

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delbel
I had a similar idea like this, but using shortwave instead of DVB.

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sgy
Are we going to witness another Clinkle sotry
([http://www.businessinsider.com/inside-story-of-
clinkle-2014-...](http://www.businessinsider.com/inside-story-of-
clinkle-2014-4))?

