5 ms·

Tomorrow's Apps Will Come From the Bitcoin Protocol

66 points by svenkatesh 13y ago

eximius 13y ago
Did anyone else get bothered by the author saying that the Bitcoin Blockchain is more like a cloud service than P2P services? The Blockchain is literally almost exactly like P2P File sharing except the file can be updated across nodes in an extremely limited context.
- dvanduzer 13y ago
  She's saying some subtle things about what a "system" is. BitCoin and BitTorrent have almost nothing in common as protocols go. At a high level, BitTorrent's DHT uses some notion of consensus to communicate between peers about who is on the network and where they and their files are. There is never system-wide coherence of the DHT, but the algorithm (Kademlia) doesn't require anything like that. BitCoin's notion of consensus requires that coherence in all but the last ~10 minutes worth of the blockchain. Zooming out even farther, BitCoin requires the entire network for anything to happen at all. BitTorrent leverages the entire network to speed up interactions between two individual nodes. If you're still not convinced, consider what happens if 40% of the network is cut off from the rest for a large period of time. After the extended network partition ends, and the two big swarms rejoin, what do users find is different?
- njyx 13y ago
  Bitcoin as is, is more like a cloud service - you need the whole chain to be updated everywhere. You can do that P2P but you need full consistency. That's not a great property if you only have weak connections between nodes.
- sroerick 13y ago
  I think bitcoin is probably the closest thing we truly have to a "cloud". P2P requires seeds and peers. The structure of the Bitcoin network means that as long as there are miners, any information stored on the blockchain will continue to exist. This, in my opinion, makes it much more similar to the idea of a "cloud" than either bittorrent, or a corporate-controlled data server that hosts your information.
betterunix 13y ago
I hope this is not the case. Bitcoin demands a massive energy investment (every watt used by the attacker must at least be matched by a watt used by the honest parties), and in the future we are going to need to be more careful about power utilization.
- wwweston 13y ago
  To emphasize the point, this isn't just true to the extent that energy is scarce: "the Earth has only one mechanism for releasing heat to space, and that’s via (infrared) radiation. We understand the phenomenon perfectly well, and can predict the surface temperature of the planet as a function of how much energy the human race produces. The upshot is that at a 2.3% growth rate (conveniently chosen to represent a 10× increase every century), we would reach boiling temperature in about 400 years. And this statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys thermodynamics, we cook ourselves with perpetual energy increase." https://physics.ucsd.edu/do-the-math/2012/04/economist-meets-physicist/ https://physics.ucsd.edu/do-the-math/2012/04/economist-meets... By making an economic exchange computationally expensive, we may have invented another way to make economic activity ecologically expensive.
  - intelliot 13y ago
    It's too early for anyone to say whether this concern is a real problem, but here are a few points that you should analyze further: 1) ASICs. In the early days of Bitcoin, one of the biggest concerns was: "Now that computational power is worth real money, aren't malicious hackers going to become rich and powerful by harnessing botnets? And more normal people's computers will join botnets as hackers are directly incentivized, by bitcoin mining, to exploit users more often." With the rise of the Bitcoin-specific ASIC, that suddenly became a total non-issue. It's completely worthless for a normal desktop PC to mine for bitcoins now: their total computational power, as measured in SHA256 hashes per second, is a tiny drop in the ocean compared to the high-end ASICs that are mining today. Problem solved. Though governments will try to get involved, and no one can definitively predict the winner in advance -- I believe it's most likely that private industry, incentivized by Bitcoin's mining rewards, will create the most advanced specialized chips for Bitcoin. They're already pushing much lower nanometer processes than general purpose CPUs! 2) Energy expense of current monetary system. People, computers, ATMs, POS's, paper, time expenditure, inflation/hyperinflation, uncertainty, economic/debt crises, counterfeiting, unemployment - all problems that could be reduced or eliminated by Bitcoin. 3) Future technology. Before cars were invented, one of the biggest concerns was: "How are we going to get rid of the horse manure that's piling up in the world's densest cities?" Infrared radiation isn't the only way to release heat to space. And even if it were, no one could say that it's not possible for humans+technology to amplify/improve this process.
ZachPruckowski 13y ago
Have they solved the "you need the whole blockchain" bit? Like do blockchain-based apps still require you to download the whole she-bang to participate? I know for bitcoin the blockchain is like 14GB or so, and that's for (only most of the) financial transactions for a small (on a global scale) community. If you want to do something with a bigger target audience or more complex data needs, are you going to wind up needing a separate hard drive to participate after a year or two?
- njyx 13y ago
  I guess if you are using the protocols for different things you can have different blockchains for every application - so that segments the effort. This is a major problem though.
- atmosx 13y ago
  The blockchain can sit on a server. As long as you trust the server...
- wmf 13y ago
  A lot of transactions can be pruned out of the Bitcoin blockchain (this isn't actually done today, but it is possible), so other blockchain-based systems would be wise to design their data formats to allow efficient pruning.
  - deleted 13y ago
    [deleted]
- philrapo 13y ago
  >"Have they solved the 'you need the whole blockchain' bit?" Yes. Ripple servers only need the current state of the ledger (as opposed to requiring the entire history of transactions, as Bitcoin does). This eliminates the problem of needing to download GBs of history to run a server. You can optionally download the full ledger history if you want access to the data, but it is not required for your server to participate in transaction processing. It's a much lighter weight design in general.
joaomsa 13y ago
Are there any resources that go in depth about how the blockchain works or how it differs from traditional DHT implementations?
- gelutu 13y ago
  Bitcoin whitepaper by Satoshi Nakamoto.
- dvanduzer 13y ago
  This is Bruce Schneier's favorite explanation of the blockchain: http://www.michaelnielsen.org/ddi/how-the-bitcoin-protocol-actually-works/ http://www.michaelnielsen.org/ddi/how-the-bitcoin-protocol-a... Comparing it to a "traditional DHT" is like kind of like comparing SQL and NoSQL. This is a good start on why that doesn't work: http://codahale.com/you-cant-sacrifice-partition-tolerance/ http://codahale.com/you-cant-sacrifice-partition-tolerance/
al2o3cr 13y ago
Needed: Markov-chain creation of Bitcoin articles as-a-service.
EGreg 13y ago
I also don't really understand WHY you need all that massive expenditure of energy for a distributed timestamp server to work. All you need is a network of computers that agree to run timestamp services, and then sign any info with enough timestamps from enough computers. That will give an uppsr bound on the time something was signed. The lower bound is trivial to provide by the transaction originator - simply sign something using enough timestamp services values as a salt. A timestamp service simply outputs a random number for each previous minute and is available to sign things using the next number. In order to defeat this scheme, an attacker needs to execute a Sybil attack against all the timestamp servers. The only time you really NEED to make something really expensive is to be let in as a timestamp server. This can be done on a reputation system, essentially proof of stake for new miners only. But not for each transaction!

66 points by svenkatesh 13y ago

Did anyone else get bothered by the author saying that the Bitcoin Blockchain is more like a cloud service than P2P services? The Blockchain is literally almost exactly like P2P File sharing except the file can be updated across nodes in an extremely limited context.

dvanduzer 13y ago
She's saying some subtle things about what a "system" is. BitCoin and BitTorrent have almost nothing in common as protocols go. At a high level, BitTorrent's DHT uses some notion of consensus to communicate between peers about who is on the network and where they and their files are. There is never system-wide coherence of the DHT, but the algorithm (Kademlia) doesn't require anything like that. BitCoin's notion of consensus requires that coherence in all but the last ~10 minutes worth of the blockchain. Zooming out even farther, BitCoin requires the entire network for anything to happen at all. BitTorrent leverages the entire network to speed up interactions between two individual nodes. If you're still not convinced, consider what happens if 40% of the network is cut off from the rest for a large period of time. After the extended network partition ends, and the two big swarms rejoin, what do users find is different?
njyx 13y ago
Bitcoin as is, is more like a cloud service - you need the whole chain to be updated everywhere. You can do that P2P but you need full consistency. That's not a great property if you only have weak connections between nodes.
sroerick 13y ago
I think bitcoin is probably the closest thing we truly have to a "cloud". P2P requires seeds and peers. The structure of the Bitcoin network means that as long as there are miners, any information stored on the blockchain will continue to exist. This, in my opinion, makes it much more similar to the idea of a "cloud" than either bittorrent, or a corporate-controlled data server that hosts your information.

betterunix 13y ago

I hope this is not the case. Bitcoin demands a massive energy investment (every watt used by the attacker must at least be matched by a watt used by the honest parties), and in the future we are going to need to be more careful about power utilization.

wwweston 13y ago
To emphasize the point, this isn't just true to the extent that energy is scarce: "the Earth has only one mechanism for releasing heat to space, and that’s via (infrared) radiation. We understand the phenomenon perfectly well, and can predict the surface temperature of the planet as a function of how much energy the human race produces. The upshot is that at a 2.3% growth rate (conveniently chosen to represent a 10× increase every century), we would reach boiling temperature in about 400 years. And this statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys thermodynamics, we cook ourselves with perpetual energy increase." https://physics.ucsd.edu/do-the-math/2012/04/economist-meets-physicist/ https://physics.ucsd.edu/do-the-math/2012/04/economist-meets... By making an economic exchange computationally expensive, we may have invented another way to make economic activity ecologically expensive.
- intelliot 13y ago
  It's too early for anyone to say whether this concern is a real problem, but here are a few points that you should analyze further: 1) ASICs. In the early days of Bitcoin, one of the biggest concerns was: "Now that computational power is worth real money, aren't malicious hackers going to become rich and powerful by harnessing botnets? And more normal people's computers will join botnets as hackers are directly incentivized, by bitcoin mining, to exploit users more often." With the rise of the Bitcoin-specific ASIC, that suddenly became a total non-issue. It's completely worthless for a normal desktop PC to mine for bitcoins now: their total computational power, as measured in SHA256 hashes per second, is a tiny drop in the ocean compared to the high-end ASICs that are mining today. Problem solved. Though governments will try to get involved, and no one can definitively predict the winner in advance -- I believe it's most likely that private industry, incentivized by Bitcoin's mining rewards, will create the most advanced specialized chips for Bitcoin. They're already pushing much lower nanometer processes than general purpose CPUs! 2) Energy expense of current monetary system. People, computers, ATMs, POS's, paper, time expenditure, inflation/hyperinflation, uncertainty, economic/debt crises, counterfeiting, unemployment - all problems that could be reduced or eliminated by Bitcoin. 3) Future technology. Before cars were invented, one of the biggest concerns was: "How are we going to get rid of the horse manure that's piling up in the world's densest cities?" Infrared radiation isn't the only way to release heat to space. And even if it were, no one could say that it's not possible for humans+technology to amplify/improve this process.

ZachPruckowski 13y ago

Have they solved the "you need the whole blockchain" bit? Like do blockchain-based apps still require you to download the whole she-bang to participate? I know for bitcoin the blockchain is like 14GB or so, and that's for (only most of the) financial transactions for a small (on a global scale) community. If you want to do something with a bigger target audience or more complex data needs, are you going to wind up needing a separate hard drive to participate after a year or two?

njyx 13y ago
I guess if you are using the protocols for different things you can have different blockchains for every application - so that segments the effort. This is a major problem though.
atmosx 13y ago
The blockchain can sit on a server. As long as you trust the server...
wmf 13y ago
A lot of transactions can be pruned out of the Bitcoin blockchain (this isn't actually done today, but it is possible), so other blockchain-based systems would be wise to design their data formats to allow efficient pruning.
- deleted 13y ago
  [deleted]
philrapo 13y ago
>"Have they solved the 'you need the whole blockchain' bit?" Yes. Ripple servers only need the current state of the ledger (as opposed to requiring the entire history of transactions, as Bitcoin does). This eliminates the problem of needing to download GBs of history to run a server. You can optionally download the full ledger history if you want access to the data, but it is not required for your server to participate in transaction processing. It's a much lighter weight design in general.

joaomsa 13y ago

Are there any resources that go in depth about how the blockchain works or how it differs from traditional DHT implementations?

gelutu 13y ago
Bitcoin whitepaper by Satoshi Nakamoto.
dvanduzer 13y ago
This is Bruce Schneier's favorite explanation of the blockchain: http://www.michaelnielsen.org/ddi/how-the-bitcoin-protocol-actually-works/ http://www.michaelnielsen.org/ddi/how-the-bitcoin-protocol-a... Comparing it to a "traditional DHT" is like kind of like comparing SQL and NoSQL. This is a good start on why that doesn't work: http://codahale.com/you-cant-sacrifice-partition-tolerance/ http://codahale.com/you-cant-sacrifice-partition-tolerance/

al2o3cr 13y ago

Needed: Markov-chain creation of Bitcoin articles as-a-service.

EGreg 13y ago

I also don't really understand WHY you need all that massive expenditure of energy for a distributed timestamp server to work. All you need is a network of computers that agree to run timestamp services, and then sign any info with enough timestamps from enough computers. That will give an uppsr bound on the time something was signed. The lower bound is trivial to provide by the transaction originator - simply sign something using enough timestamp services values as a salt. A timestamp service simply outputs a random number for each previous minute and is available to sign things using the next number. In order to defeat this scheme, an attacker needs to execute a Sybil attack against all the timestamp servers. The only time you really NEED to make something really expensive is to be let in as a timestamp server. This can be done on a reputation system, essentially proof of stake for new miners only. But not for each transaction!