4 ms·

The adjustment is by block-count not time, if they only produce a block per day it'll take ~144 days to lower the difficulty. I think people would abandon long

by eterm 9y ago

The adjustment is by block-count not time, if they only produce a block per day it'll take ~144 days to lower the difficulty. I think people would abandon long before that.

deleted 9y ago
[deleted]
hybridsole 9y ago
The difficulty recalculation in Bitcoin ABC was reduced significantly. I believe it is 6 blocks but could be wrong. At most it would take several days as opposed to several weeks.
elmar 9y ago
they probably should have hardcoded a much lower dificulty for the first batch of blocks.
simias 9y ago
There's a "cheat" to avoid this situation in the technical spec[1]: In case the MTP of the tip of the chain is 12h or more after the MTP 6 block before the tip, the proof of work target is increased by a quarter, or 25%, which corresponds to a difficulty reduction of 20%. So as long as the BCC keeps lagging behind massively (less than 6 blocks every 12h) the difficulty is reduced by 20% after every new block. [1] https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-technical-spec.md#req-7-difficulty-adjustement-in-case-of-hashrate-drop https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-techni...
- eterm 9y ago
  Thanks I didn't know of that 'cheat', it sounds from the spec though that the difficulty of the block yet to be found would be reduced but it would then go back up for the block after that to the proper-set difficultly (because there would now be a block within the 12h window).
  - simias 9y ago
    It's computed over 6 blocks: "the MTP of the tip of the chain is 12h or more after the MTP 6 block before the tip". So it takes 6 consecutive blocks to be found "fast enough" (that is, within a 12h window) to return to the normal difficulty algorithm.
    - Santzes 9y ago
      Couldn't big miners play this by mining 6 blocks of Bitcoin Cash and then letting it rot without blocks?
      - simias 9y ago
        Only possible if the colluding miners have almost all the hashing power to themselves (to mine 6 consecutive blocks faster than everybody else). If that's the case then those miners can do anything they want anyway, including double-spending money[1]. Furthermore if they really only wanted to slow down BCC and nothing else it still wouldn't be very efficient. They'd just postpone the scaling for the next 6 blocks and then the rule would kick in again. So they'd have to keep make sure that they're always just at the limit of 6 blocks per 12 hours... but at this point you're actually mining block and contributing to the ecosystem, so there's no problem. [1] https://bitcoin.org/en/glossary/51-percent-attack https://bitcoin.org/en/glossary/51-percent-attack
        Santzes 9y ago
        Ahh I thought this 20% drop per 6 blocks was only after the split block and would end after the first 6 blocks mined in 12h, would have been too easy to game that one. Looks like though they're getting blocks now, 4 blocks in less than two hours.

by eterm 9y ago

The adjustment is by block-count not time, if they only produce a block per day it'll take ~144 days to lower the difficulty. I think people would abandon long before that.

deleted 9y ago

[deleted]

hybridsole 9y ago

The difficulty recalculation in Bitcoin ABC was reduced significantly. I believe it is 6 blocks but could be wrong. At most it would take several days as opposed to several weeks.

elmar 9y ago

they probably should have hardcoded a much lower dificulty for the first batch of blocks.

simias 9y ago

There's a "cheat" to avoid this situation in the technical spec[1]: In case the MTP of the tip of the chain is 12h or more after the MTP 6 block before the tip, the proof of work target is increased by a quarter, or 25%, which corresponds to a difficulty reduction of 20%. So as long as the BCC keeps lagging behind massively (less than 6 blocks every 12h) the difficulty is reduced by 20% after every new block. [1] https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-technical-spec.md#req-7-difficulty-adjustement-in-case-of-hashrate-drop https://github.com/Bitcoin-UAHF/spec/blob/master/uahf-techni...

eterm 9y ago
Thanks I didn't know of that 'cheat', it sounds from the spec though that the difficulty of the block yet to be found would be reduced but it would then go back up for the block after that to the proper-set difficultly (because there would now be a block within the 12h window).
- simias 9y ago
  It's computed over 6 blocks: "the MTP of the tip of the chain is 12h or more after the MTP 6 block before the tip". So it takes 6 consecutive blocks to be found "fast enough" (that is, within a 12h window) to return to the normal difficulty algorithm.
  - Santzes 9y ago
    Couldn't big miners play this by mining 6 blocks of Bitcoin Cash and then letting it rot without blocks?
    - simias 9y ago
      Only possible if the colluding miners have almost all the hashing power to themselves (to mine 6 consecutive blocks faster than everybody else). If that's the case then those miners can do anything they want anyway, including double-spending money[1]. Furthermore if they really only wanted to slow down BCC and nothing else it still wouldn't be very efficient. They'd just postpone the scaling for the next 6 blocks and then the rule would kick in again. So they'd have to keep make sure that they're always just at the limit of 6 blocks per 12 hours... but at this point you're actually mining block and contributing to the ecosystem, so there's no problem. [1] https://bitcoin.org/en/glossary/51-percent-attack https://bitcoin.org/en/glossary/51-percent-attack
      - Santzes 9y ago
        Ahh I thought this 20% drop per 6 blocks was only after the split block and would end after the first 6 blocks mined in 12h, would have been too easy to game that one. Looks like though they're getting blocks now, 4 blocks in less than two hours.