5 ms·

If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it, or cease to transact. The longest chain is always the

If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it, or cease to transact. The longest chain is always the most valuable.

ateevchopra 9y ago
If miners chose to mine on a chain that no-one wants, they'll run into losses. Users will probably move to some other chain. As an example: Bitcoin users might wanna switch to Litecoin. And guess what miners will do then ?
KirinDave 9y ago
You're also referring to a major weakness in the distributed consensus of bitcoin: the longest-chain-preferred mechanism is almost certainly a vector of attack on the chain.
- simias 9y ago
  Wouldn't you need to have a majority of the hash power to fork the chain and generate a longer one anyway? I think it's well understood that anybody managing to go above 50% of the hash capacity effectively "rules" the currency.
  - KirinDave 9y ago
    This is a common response to this but I don't think it's true in every case. I think if your goal is strictly to disrupt the Bitcoin service you can accomplish that by disrupting and attacking individual nodes in parallel and letting the resulting chaos from these cheaper attacks widen the scope of your disruption, stepwise.
- wildbunny 9y ago
  On the contrary, this is the major strength of the system.
  - KirinDave 9y ago
    If by strength you mean, "A clear methodology from which a sufficiently large ec2 buy can rapidly fragment the Bitcoin consensus" then yes, I suppose that's fantastic. From the perspective of people transacting on Bitcoin's infrastructure I suspect they'd call it "an attack."
    - DINKDINK 9y ago
      >a sufficiently large ec2 buy can rapidly fragment the Bitcoin consensus You grossly underestimate the hashing capacity of the bitcoin network. The hashing capacity, at time of posting, is approximately 5,000,000,000 Gigahashes/second[1]. Spot measurement of the hashing capacity of an EC2 instance is 0.4 Gigahashes/second[2]. You would need 12 BILLION EC2 instances to 51% attack the bitcoin network.[3] Using EC2 to attack the network is impractical and inefficient. [1] https://bitcoinwisdom.com/bitcoin/difficulty https://bitcoinwisdom.com/bitcoin/difficulty [2] https://www.reddit.com/r/Bitcoin/comments/1btgl1/i_was_curious_so_i_briefly_setup_a_miner_in_an/ https://www.reddit.com/r/Bitcoin/comments/1btgl1/i_was_curio... [3] x/(5e18+x)=.51 y=x/.4e8
      - codeisawesome 9y ago
        In the OP, the author says there are "approximately 5,000 computers" in the bitcoin network. I'm curious if you believe this is right too? Those are some powerful computers... (yes, "duh" indeed, I'm still awed).
        Slartie 9y ago
        That could very well be true. All mining for BTC is done via ASICs now, specialized silicon that just hashes crazy fast, but can't even get a TCP connection up and running. For networking, a bunch of ASIC chips is typically connected to some embedded computer, and even that usually isn't a direct peer on the Bitcoin network, but only connected to a mining pool server with hundreds of other such ASIC controllers. And this server then is the first actual part of the Bitcoin p2p network, single-handedly representing a mind-boggling multi-Megawatt hash power infrastructure. Even most BTC users do not run actual clients anymore but use exchanges or wallet services which bundle huge numbers of users behind few actual Bitcoin network nodes.
DINKDINK 9y ago
>If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it No, if the miners mine on a chain that doesn't meet consensus rules, users will not follow it. If miners decide that the coinbase issuance schedule isn't to their liking, and decide to revert it back to 50 bitcoins per block, users will reject those blocks. This is a fundamental governance property of a blockchain.
- stale2002 9y ago
  Kinda sorta. Yes, users can reject Hard Forks. But the problem is that soft forks can do basically anything. Yes, even increase the block reward, in a roundabout way, (by using added extension blocks that have special rules, and then requiring all transactions to go through the extension blocks.) Although from the perspective of a non-conforming Node, this would just look like a DDOS style mining empty blocks attack. At this point the only thing that users can do is change the Proof of Work algorithm. .... But, if the big players in mining have a bunch of GPUs on standby... well, it is not even guaranteed that this will work.
rlpb 9y ago
> The longest chain is always the most valuable. Only the longest chain that users consider legitimate. If users reach consensus on using rules that have lower transaction costs, it won't matter how long miners mine their higher transaction cost chain. The big question is: can users achieve such consensus politically, or in practice do the miners lead the users because they need less organization to do so?

If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it, or cease to transact. The longest chain is always the most valuable.

ateevchopra 9y ago

If miners chose to mine on a chain that no-one wants, they'll run into losses. Users will probably move to some other chain. As an example: Bitcoin users might wanna switch to Litecoin. And guess what miners will do then ?

KirinDave 9y ago

You're also referring to a major weakness in the distributed consensus of bitcoin: the longest-chain-preferred mechanism is almost certainly a vector of attack on the chain.

simias 9y ago
Wouldn't you need to have a majority of the hash power to fork the chain and generate a longer one anyway? I think it's well understood that anybody managing to go above 50% of the hash capacity effectively "rules" the currency.
- KirinDave 9y ago
  This is a common response to this but I don't think it's true in every case. I think if your goal is strictly to disrupt the Bitcoin service you can accomplish that by disrupting and attacking individual nodes in parallel and letting the resulting chaos from these cheaper attacks widen the scope of your disruption, stepwise.
wildbunny 9y ago
On the contrary, this is the major strength of the system.
- KirinDave 9y ago
  If by strength you mean, "A clear methodology from which a sufficiently large ec2 buy can rapidly fragment the Bitcoin consensus" then yes, I suppose that's fantastic. From the perspective of people transacting on Bitcoin's infrastructure I suspect they'd call it "an attack."
  - DINKDINK 9y ago
    >a sufficiently large ec2 buy can rapidly fragment the Bitcoin consensus You grossly underestimate the hashing capacity of the bitcoin network. The hashing capacity, at time of posting, is approximately 5,000,000,000 Gigahashes/second[1]. Spot measurement of the hashing capacity of an EC2 instance is 0.4 Gigahashes/second[2]. You would need 12 BILLION EC2 instances to 51% attack the bitcoin network.[3] Using EC2 to attack the network is impractical and inefficient. [1] https://bitcoinwisdom.com/bitcoin/difficulty https://bitcoinwisdom.com/bitcoin/difficulty [2] https://www.reddit.com/r/Bitcoin/comments/1btgl1/i_was_curious_so_i_briefly_setup_a_miner_in_an/ https://www.reddit.com/r/Bitcoin/comments/1btgl1/i_was_curio... [3] x/(5e18+x)=.51 y=x/.4e8
    - codeisawesome 9y ago
      In the OP, the author says there are "approximately 5,000 computers" in the bitcoin network. I'm curious if you believe this is right too? Those are some powerful computers... (yes, "duh" indeed, I'm still awed).
      - Slartie 9y ago
        That could very well be true. All mining for BTC is done via ASICs now, specialized silicon that just hashes crazy fast, but can't even get a TCP connection up and running. For networking, a bunch of ASIC chips is typically connected to some embedded computer, and even that usually isn't a direct peer on the Bitcoin network, but only connected to a mining pool server with hundreds of other such ASIC controllers. And this server then is the first actual part of the Bitcoin p2p network, single-handedly representing a mind-boggling multi-Megawatt hash power infrastructure. Even most BTC users do not run actual clients anymore but use exchanges or wallet services which bundle huge numbers of users behind few actual Bitcoin network nodes.

DINKDINK 9y ago

>If miners chose to mine on a chain that no-one wants, then everybody has to grudgingly go along with it No, if the miners mine on a chain that doesn't meet consensus rules, users will not follow it. If miners decide that the coinbase issuance schedule isn't to their liking, and decide to revert it back to 50 bitcoins per block, users will reject those blocks. This is a fundamental governance property of a blockchain.

stale2002 9y ago
Kinda sorta. Yes, users can reject Hard Forks. But the problem is that soft forks can do basically anything. Yes, even increase the block reward, in a roundabout way, (by using added extension blocks that have special rules, and then requiring all transactions to go through the extension blocks.) Although from the perspective of a non-conforming Node, this would just look like a DDOS style mining empty blocks attack. At this point the only thing that users can do is change the Proof of Work algorithm. .... But, if the big players in mining have a bunch of GPUs on standby... well, it is not even guaranteed that this will work.

rlpb 9y ago

> The longest chain is always the most valuable. Only the longest chain that users consider legitimate. If users reach consensus on using rules that have lower transaction costs, it won't matter how long miners mine their higher transaction cost chain. The big question is: can users achieve such consensus politically, or in practice do the miners lead the users because they need less organization to do so?