7 ms·

Kryptoradio – A Bitcoin data transmission system

204 points by mappum 12y ago

bagosm 12y ago
Thats all good and gimmicky but can you tell me: the 1-way connection offers any value to anyone?
- danwills 12y ago
  Could it be used for things like vending machines perhaps? You would still need a cellphone to pay but the machine would only need an antenna and cheapish chip to make it work.
  - ispshadow 12y ago
    That's an incredible idea.
  - aw3c2 12y ago
    And I just need a tiny DVB-T transmitter to feed my own blockchain to it. I like that idea of yours! :P
    - olalonde 12y ago
      Except you wouldn't be able to generate valid blocks fast enough (confirm new transactions) unless you had massive hashing power (in which case you might as well go for a 51% attack against the Bitcoin network itself).
    - StavrosK 12y ago
      If only there were some way to cryptographically sign stuff...
  - Retric 12y ago
    Sure, if your willing to wait 20+ minutes to get your drink.
    - wyager 12y ago
      >Sure, if your willing to wait 20+ minutes to get your drink. This is a fundamental misunderstanding people have about Bitcoin. A bitcoin before a block confirmation ~ A credit card before 180 days. There is a small possibility of "undoing" a transaction before a block confirmation, just like there is a small possibility of a customer doing a credit card chargeback before the credit card payment clears. However, it's a pain in the ass (even moreso with Bitcoin), isn't reliable with Bitcoin, and almost no one ever does it. For small transactions like buying soda from a vending machine, waiting 2 seconds for the transaction to propagate is more than enough. The only time I would ever wait for a block confirmation is if I was doing a transaction in the thousands of dollars range.
      - Retric 12y ago
        There are several ways you can implement this, but unless you wait occasional double spends are fairly easy to pull off. To put it simply unconfirmed transactions take a while to propegate and don't instantly decrement your wallet. True a single small transaction might not seem like much, but it's anonymous and even a small chance of success chance is going to be with it to some people. PS: A 51% attack is only needed to counter confirmed transactions unconfirmed transactions have little protection and take a while to get confirmed.
        mappum 12y ago
        Double spends would be hard enough that it is not worth it for low-value transactions. The operator of Ghash would have a 30% chance of pulling it off, but that problem would be solved if hashpower/pool concentration gets solved.
        deleted 12y ago
        [deleted]
        Retric 12y ago
        You don't need lot's of having power a new transaction with a higher transaction fee can get you there ~10-20% of the time. For small anonimus transactions like a vending machine that's not a problem. Add a slick UI and an suddenly lot's of people are going for random "Free" soda.
- servowire 12y ago
  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)
  - asdfaoeu 12y ago
    Why not just send the confirmation back by SMS?
    - zouppen 12y ago
      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.
    - servowire 12y ago
      That would require trust - in the form of the SMS provider. No way to verify that SMS is valid, it could have been forged. The proof-of-work blockchain transmission means it's the real and proper blockchain and is valid.
  - wyager 12y ago
    >Would take about 15 seconds to complete That's unfortunately not sufficient at modern transaction rates. Is there any reason you chose DTMF in particular?
- VMG 12y ago
  Yes, for the same reason a radio broadcast does. Distribute valuable information (mined blocks and verified transactions) with a nearly constant cost in relation to the recipients.
- FatalLogic 12y ago
  It's a huge amount of 'free' bandwidth, and a one-way WAN connection can still be useful. It is only at the stage of a gimmick, or a proof of concept, but if the broadcast service could be relied upon long term, then it might greatly reduce the bandwidth and connectivity costs for simple Bitcoin-enabled devices. It's misleading to think of it as only a one-way connection, because a user naturally creates a two-way channel. Imagine a situation where a user sends a payment to the blockchain, via mobile internet, which is then picked up by the device. That is a de facto two-way connection. The user's phone (or whatever) would communicate with the device by a local area connection, such as Wifi, QR code, Bluetooth, even a typed code etc. Obviously, devices could also have a low bandwidth uplink connection, such as 3g, but it's interesting to think about how it might still be useful with only a 1-way connection. It depends somewhat on the rate and structure of the blockchain data transmission.
deleted 12y ago
[deleted]
- mappum 12y ago
  Right, and the full blockchain via radio plus SPV via the internet would allow full nodes to use this without trusting the centralized broadcaster.
jtanner 12y ago
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?
- pronoiac 12y ago
  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 12y ago
    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.
    - zouppen 12y ago
      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.
- kylebrown 12y ago
  The idea is that a lot of devices wouldn't need a two-way connection, rather they could confirm payment with only a downlink.
deleted 12y ago
[deleted]
johnyzee 12y ago
This means parking meters, vending machines, laundromats, etc. can receive bitcoin payments without an internet connection. That is actually really cool.
- sspiff 12y ago
  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).
  - mappum 12y ago
    Not necessarily. If the installer of the machine checks that it downloaded the "real" blockchain, it would be expensive to forge new blocks to send to it.
  - makomk 12y ago
    DVB-T tuners are pretty cheap because they're highly integrated and mass produced in huge numbers - you can get USB receiver dongles for under $10 in single quantities. There are even SoCs that integrate a processor and DVB-T demodulator on a single chip, usually used for stuff like set-top boxes.
    - eric_bullington 12y ago
      >There are even SoCs that integrate a processor and DVB-T demodulator on a single chip, usually used for stuff like set-top boxes. Are there any such chips other than the Broadcom chip that was announced last year?
      - makomk 12y ago
        Yeah, several companies make them, they're very popular in cheap set-top boxes. Having found what I think is the Broadcom press release you're referring to[1], the thing that's unique about their SoC is that it supports DVB-T2 which is newer and less widely used or supported. Looks like ALi have just announced a SoC for that too[2], though unlike Broadcom's it requires a seperate tuner chip. [1] http://www.broadcom.com/press/release.php?id=s736006 http://www.broadcom.com/press/release.php?id=s736006 [2] http://www.digitaltvnews.net/?p=24266 http://www.digitaltvnews.net/?p=24266
acd 12y ago
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.
- oleganza 12y ago
  How wikipedia is different from any other website useful for victims of police state?
  - Mangalor 12y ago
    It's an encyclopedia of everything.
- zouppen 12y ago
  We can do it. It's just data. Of course long waves carry very scarce amounts of traffic. DVB-T or even better approach would be using satellite. There are digital satellite technologies like DVB-S which could carry that kind of data. It's only a financial issue.
- mike_hearn 12y ago
  It just moves the thing that gets censored from the website itself to the equipment needed to receive it.
  - Tycho 12y ago
    Which is infinitely harder for authorities to control.
delbel 12y ago
I had a similar idea like this, but using shortwave instead of DVB.
sgy 12y ago
Are we going to witness another Clinkle sotry (http://www.businessinsider.com/inside-story-of-clinkle-2014-4 http://www.businessinsider.com/inside-story-of-clinkle-2014-...)?

204 points by mappum 12y ago

bagosm 12y ago

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

danwills 12y ago
Could it be used for things like vending machines perhaps? You would still need a cellphone to pay but the machine would only need an antenna and cheapish chip to make it work.
- ispshadow 12y ago
  That's an incredible idea.
- aw3c2 12y ago
  And I just need a tiny DVB-T transmitter to feed my own blockchain to it. I like that idea of yours! :P
  - olalonde 12y ago
    Except you wouldn't be able to generate valid blocks fast enough (confirm new transactions) unless you had massive hashing power (in which case you might as well go for a 51% attack against the Bitcoin network itself).
  - StavrosK 12y ago
    If only there were some way to cryptographically sign stuff...
- Retric 12y ago
  Sure, if your willing to wait 20+ minutes to get your drink.
  - wyager 12y ago
    >Sure, if your willing to wait 20+ minutes to get your drink. This is a fundamental misunderstanding people have about Bitcoin. A bitcoin before a block confirmation ~ A credit card before 180 days. There is a small possibility of "undoing" a transaction before a block confirmation, just like there is a small possibility of a customer doing a credit card chargeback before the credit card payment clears. However, it's a pain in the ass (even moreso with Bitcoin), isn't reliable with Bitcoin, and almost no one ever does it. For small transactions like buying soda from a vending machine, waiting 2 seconds for the transaction to propagate is more than enough. The only time I would ever wait for a block confirmation is if I was doing a transaction in the thousands of dollars range.
    - Retric 12y ago
      There are several ways you can implement this, but unless you wait occasional double spends are fairly easy to pull off. To put it simply unconfirmed transactions take a while to propegate and don't instantly decrement your wallet. True a single small transaction might not seem like much, but it's anonymous and even a small chance of success chance is going to be with it to some people. PS: A 51% attack is only needed to counter confirmed transactions unconfirmed transactions have little protection and take a while to get confirmed.
      - mappum 12y ago
        Double spends would be hard enough that it is not worth it for low-value transactions. The operator of Ghash would have a 30% chance of pulling it off, but that problem would be solved if hashpower/pool concentration gets solved.
        deleted 12y ago
        [deleted]
        Retric 12y ago
        You don't need lot's of having power a new transaction with a higher transaction fee can get you there ~10-20% of the time. For small anonimus transactions like a vending machine that's not a problem. Add a slick UI and an suddenly lot's of people are going for random "Free" soda.
servowire 12y ago
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)
- asdfaoeu 12y ago
  Why not just send the confirmation back by SMS?
  - zouppen 12y ago
    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.
  - servowire 12y ago
    That would require trust - in the form of the SMS provider. No way to verify that SMS is valid, it could have been forged. The proof-of-work blockchain transmission means it's the real and proper blockchain and is valid.
- wyager 12y ago
  >Would take about 15 seconds to complete That's unfortunately not sufficient at modern transaction rates. Is there any reason you chose DTMF in particular?
VMG 12y ago
Yes, for the same reason a radio broadcast does. Distribute valuable information (mined blocks and verified transactions) with a nearly constant cost in relation to the recipients.
FatalLogic 12y ago
It's a huge amount of 'free' bandwidth, and a one-way WAN connection can still be useful. It is only at the stage of a gimmick, or a proof of concept, but if the broadcast service could be relied upon long term, then it might greatly reduce the bandwidth and connectivity costs for simple Bitcoin-enabled devices. It's misleading to think of it as only a one-way connection, because a user naturally creates a two-way channel. Imagine a situation where a user sends a payment to the blockchain, via mobile internet, which is then picked up by the device. That is a de facto two-way connection. The user's phone (or whatever) would communicate with the device by a local area connection, such as Wifi, QR code, Bluetooth, even a typed code etc. Obviously, devices could also have a low bandwidth uplink connection, such as 3g, but it's interesting to think about how it might still be useful with only a 1-way connection. It depends somewhat on the rate and structure of the blockchain data transmission.

deleted 12y ago

[deleted]

mappum 12y ago
Right, and the full blockchain via radio plus SPV via the internet would allow full nodes to use this without trusting the centralized broadcaster.

jtanner 12y ago

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?

pronoiac 12y ago
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 12y ago
  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.
  - zouppen 12y ago
    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.
kylebrown 12y ago
The idea is that a lot of devices wouldn't need a two-way connection, rather they could confirm payment with only a downlink.

deleted 12y ago

[deleted]

johnyzee 12y ago

This means parking meters, vending machines, laundromats, etc. can receive bitcoin payments without an internet connection. That is actually really cool.

sspiff 12y ago
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).
- mappum 12y ago
  Not necessarily. If the installer of the machine checks that it downloaded the "real" blockchain, it would be expensive to forge new blocks to send to it.
- makomk 12y ago
  DVB-T tuners are pretty cheap because they're highly integrated and mass produced in huge numbers - you can get USB receiver dongles for under $10 in single quantities. There are even SoCs that integrate a processor and DVB-T demodulator on a single chip, usually used for stuff like set-top boxes.
  - eric_bullington 12y ago
    >There are even SoCs that integrate a processor and DVB-T demodulator on a single chip, usually used for stuff like set-top boxes. Are there any such chips other than the Broadcom chip that was announced last year?
    - makomk 12y ago
      Yeah, several companies make them, they're very popular in cheap set-top boxes. Having found what I think is the Broadcom press release you're referring to[1], the thing that's unique about their SoC is that it supports DVB-T2 which is newer and less widely used or supported. Looks like ALi have just announced a SoC for that too[2], though unlike Broadcom's it requires a seperate tuner chip. [1] http://www.broadcom.com/press/release.php?id=s736006 http://www.broadcom.com/press/release.php?id=s736006 [2] http://www.digitaltvnews.net/?p=24266 http://www.digitaltvnews.net/?p=24266

acd 12y ago

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.

oleganza 12y ago
How wikipedia is different from any other website useful for victims of police state?
- Mangalor 12y ago
  It's an encyclopedia of everything.
zouppen 12y ago
We can do it. It's just data. Of course long waves carry very scarce amounts of traffic. DVB-T or even better approach would be using satellite. There are digital satellite technologies like DVB-S which could carry that kind of data. It's only a financial issue.
mike_hearn 12y ago
It just moves the thing that gets censored from the website itself to the equipment needed to receive it.
- Tycho 12y ago
  Which is infinitely harder for authorities to control.

delbel 12y ago

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

sgy 12y ago

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