3 ms·

anyone that is upgraded just ignores their block Yes, but everyone who is not upgraded does not. So there will be two chains that hold value. One run by a

by TekMol 6y ago

anyone that is upgraded just ignores their block Yes, but everyone who is not upgraded does not. So there will be two chains that hold value. One run by a network of pre-taproot software and one run by a network of post-taproot software.

nullc 6y ago
> So there will be two chains that hold value. Nah, because the post-taproot software will have more hashpower (due to how it activates), the taproot enabled blocks are acceptable to old nodes, and Bitcoin follows the valid chain with the most hashpower. Bitcoin has introduced changes like this a good dozen times in the past, it doesn't create two separate chains in practice. The only way it can create two separate chains is if the unupgraded side has a super majority hashpower, one of them modifies their software to mine something invalid under the new 'future' rules... and no humans intervene to prevent that outcome (e.g. by getting hashpower to move). In practice this doesn't happen because the activation is triggered by 90% hashpower indicating that it will enforce. (and won't turn active until November, giving people plenty of time to upgrade)
- TekMol 6y ago
  Does the old software really have to be modified to "mine something invalid under the new 'future' rules"? Isn't it possible to simply craft a transaction that is invalid according to the new software but valid according to the old software?
  - nullc 6y ago
    The definition of valid is different in different contexts. To old nodes taproot transactions are valid when they've been included in a block, but are invalid when they are relayed on the network. This is accomplished by taking all the parts of the transaction that are reserved for future extensions and making their use invalid for the purpose of relay, mining selection, or wallet display in advance. So you can make a transaction that is invalid to new nodes, but valid-in-blocks to old but it'll still be invalid to them for other uses. It's sufficient that new stuff be considered valid in blocks by old nodes for the system to still come to consensus, since only the blocks are included in consensus. [Thanks for all the questions, BTW, it's been an interesting discussion.]
    - TekMol 6y ago
      Tricky. I agree that the sum of these circumstances make it somewhat hard to say if something like taproot creates a new currency or not. As long as the longest chain is the one with taproot transactions, then probably not.

by TekMol 6y ago

nullc 6y ago

> So there will be two chains that hold value. Nah, because the post-taproot software will have more hashpower (due to how it activates), the taproot enabled blocks are acceptable to old nodes, and Bitcoin follows the valid chain with the most hashpower. Bitcoin has introduced changes like this a good dozen times in the past, it doesn't create two separate chains in practice. The only way it can create two separate chains is if the unupgraded side has a super majority hashpower, one of them modifies their software to mine something invalid under the new 'future' rules... and no humans intervene to prevent that outcome (e.g. by getting hashpower to move). In practice this doesn't happen because the activation is triggered by 90% hashpower indicating that it will enforce. (and won't turn active until November, giving people plenty of time to upgrade)

TekMol 6y ago
Does the old software really have to be modified to "mine something invalid under the new 'future' rules"? Isn't it possible to simply craft a transaction that is invalid according to the new software but valid according to the old software?
- nullc 6y ago
  The definition of valid is different in different contexts. To old nodes taproot transactions are valid when they've been included in a block, but are invalid when they are relayed on the network. This is accomplished by taking all the parts of the transaction that are reserved for future extensions and making their use invalid for the purpose of relay, mining selection, or wallet display in advance. So you can make a transaction that is invalid to new nodes, but valid-in-blocks to old but it'll still be invalid to them for other uses. It's sufficient that new stuff be considered valid in blocks by old nodes for the system to still come to consensus, since only the blocks are included in consensus. [Thanks for all the questions, BTW, it's been an interesting discussion.]
  - TekMol 6y ago
    Tricky. I agree that the sum of these circumstances make it somewhat hard to say if something like taproot creates a new currency or not. As long as the longest chain is the one with taproot transactions, then probably not.