Blockchain Fork – Are BIP110 blocks from low difficulty points valid?

It is important to separate concepts validity (“Does this chain satisfy all validity rules?”) and be active (“Of all valid chains, which one does the most work?”).

Let’s say the two branches of the chain are: A (generated by Bitcoin miners) and B (Generated by BIP110 miners). A It’s about 10 times more work. BHowever, over time, after retargeting, you will have roughly the same number of blocks.

BIP110 enforcement nodes only B To be valid, an active chain is required. B. They don’t even “see”. A chain.

Bitcoin nodes have both A and B Valid. However, regardless of the number of blocks or difficulty adjustment, A The chain definitely has more proof-of-work. B (This is roughly calculated as the sum of the difficulty levels of all blocks.) Therefore, Bitcoin nodes will never be considered. B Because it becomes an active chain. A There’s so much more to do. Being “active” is what actually matters to users. B.

But if B The chain somehow ended up doing the most work at some point later (which inevitably meant overtaking). A In case of difficulties) the Bitcoin node will switch to that node.

Difficulty scaling rules (part of the validity rules) apply. per branch (As with all consensus rules): The difficulty requirement of each branch is a function of the blocks within the same branch. The existence of other branches with further difficulties is not relevant to validity. Of course, “selecting the chain with the most work” still concerns the difference in difficulty between branches (indirectly, contributing to each branch through total PoW).

Hard forks are unrelated. This is a change to the consensus rules that is not compatible in both directions. That’s not the case here. The BIP110 chain is valid for Bitcoin nodes and is inferior to proof-of-work as long as the difficulty level is low.