I understand what is hardfork in theory. Hardfork happens, when the consensus algorithm changes (if I'm wrong, correct me please). Ok, with theory everything is clear, but what about technical side of this question? How exactly hardfork occurs, how exactly chain divides? Thank you for your answers

closed as too broad by Pieter Wuille, Raghav Sood, Andrew Chow Apr 9 '18 at 15:47

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  • I think this is a confused question. You don't "make" a hardfork. It occurs whenever a group of participants within a cryptocurrency intentionally or unintentionally end up enforcing separate rules, resulting in two currencies. – Pieter Wuille Apr 7 '18 at 18:24

A new version of the software is implemented, which uses the new rules. The old software will see the new transactions/blocks generated by this new software as invalid after the fork date, while new software will accept it, so the old software and new software will disagree on the longest valid blockchain, creating a hard fork.

  • Thanks for your answer. So, to create new coin, I just need to clone bitcoin repo from github, after change something there, create new software client, which will work only with my chain and start it? – TheWorldNode Apr 7 '18 at 12:06
  • Or, I don't need to clone repository, I just need to create new software client with new rules and send a transaction to Bitcoin main chain, blockchain will understand, that this is not correct and create hard fork? – TheWorldNode Apr 7 '18 at 12:07
  • @TheWorldNode You also need to 1) choose a different network magic, 2) add replay protection if you want to create a hard fork the proper way. – MCCCS Apr 7 '18 at 13:45
  • @MCCCS Mmm, ok, replay protection I understood, but what is network magic? – TheWorldNode Apr 7 '18 at 16:17
  • Nodes connect to other nodes with the same network magic. – MCCCS Apr 7 '18 at 17:15

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