<p>The rule is to follow the strongest chain, i.e., the chain that contains the most work is considered the one the entire network should follow (the chain of truth). If a new chain appears that differs in several of blocks (even up to 20/30; maybe 100), it is not that significant problem; the network will switch to that new, stronger chain. However, what would happen if an entirely new chain starting from the genesis block appeared with more computational power than the current one? According to the rules, we should follow the strongest (the new) chain, and all nodes that don't do so would be considered invalid. But would the network really switch to this new chain? It is right to make the transition, but if it was done completely, everyone would lose their money in Bitcoin, people would lose confidence in the network, and it would completely collapse.</p>
<p>Therefore, in theory, and what is correct is to transition to the stronger chain, but would it really be done?</p>
<p>I'm not asking for predictions about the future or someone telling me what would happen in hypothetical scenarios, but I assume that people who have been involved in Bitcoin for over 5/10 years have thought about this, and discussions on this topic might have taken place in the Bitcoin community (conferences, forums, informal conversations, etc.). I expect there have been conclusions drawn from these discussions.</p>

CC BY-SA 4.0
2024-01-13T12:46:40.340Z
Sounds very similar to https://bitcoin.stackexchange.com/q/75733/101498. Basically if someone can rewrite the whole history since the genesis block then yes Bitcoin would become uninteresting.
Antoine Poinsot
CC BY-SA 4.0
2024-01-13T16:18:09.283Z
Does this answer your question? [Potential fork from genesis block using enormous computational power](https://bitcoin.stackexchange.com/questions/107144/potential-fork-from-genesis-block-using-enormous-computational-power)
RedGrittyBrick
CC BY-SA 4.0
2024-01-13T16:50:09.160Z
@RedGrittyBrick *Mike D* just wrote how that is possible only in theory. I know that. I am interested in whether such a (theoretical) scenario was discussed in the Bitcoin community and what we would do then. One of the solution (mentioned by *noone392*) is to ignore fork (ignore last blocks hash). However, in my opinion, that would not solve anything, because a new last block can be made on top of n-1 th block.
Qwerty M3
CC BY-SA 4.0
2024-01-13T16:53:31.780Z
@AntoinePoinsot Yes, I think so too. However, I was interested in what the more experienced "Bitcoin people" think about this topic.
Qwerty M3
CC BY-SA 4.0
2024-01-13T21:11:53.117Z
While not the same question, I think my answer in Antoine's link covers it. It's certainly the case that a very deep reorg is very damaging, but if it were to happen, then the assumptions that make PoW secure are just broken and there is little to be done.
Pieter Wuille
CC BY-SA 4.0
2024-01-13T22:40:22.717Z
@PieterWuille A reorganization of how many blocks deep could be considered as PoW secure is broken? I'm not asking for an exact number, but an approximate one, from experience. Would 20 block reorg be a serious hit to Bitcoins secure?
Qwerty M3
<blockchain-fork><chain-reorganization>
Would the network switch to a new chain that differ from the genesis block?
Qwerty M3
# Would the network switch to a new chain that differ from the genesis block?

(Asked by: username_0 on 2024-01-12)

The rule is to follow the strongest chain, i.e., the chain that contains the most work is considered the one the entire network should follow (the chain of truth). If a new chain appears that differs in several of blocks (even up to 20/30; maybe 100), it is not that significant problem; the network will switch to that new, stronger chain. However, what would happen if an entirely new chain starting from the genesis block appeared with more computational power than the current one? According to the rules, we should follow the strongest (the new) chain, and all nodes that don't do so would be considered invalid. But would the network really switch to this new chain? It is right to make the transition, but if it was done completely, everyone would lose their money in Bitcoin, people would lose confidence in the network, and it would completely collapse.

Therefore, in theory, and what is correct is to transition to the stronger chain, but would it really be done?

I'm not asking for predictions about the future or someone telling me what would happen in hypothetical scenarios, but I assume that people who have been involved in Bitcoin for over 5/10 years have thought about this, and discussions on this topic might have taken place in the Bitcoin community (conferences, forums, informal conversations, etc.). I expect there have been conclusions drawn from these discussions.

**Tags:** blockchain-fork, chain-reorganization

> **Comments:**
> **username_1**: Sounds very similar to https://bitcoin.stackexchange.com/q/75733/101498. Basically if someone can rewrite the whole history since the genesis block then yes Bitcoin would become uninteresting.  
> **username_2**: Does this answer your question? [Potential fork from genesis block using enormous computational power](https://bitcoin.stackexchange.com/questions/107144/potential-fork-from-genesis-block-using-enormous-computational-power)  
> **username_0**: @username_2 *Mike D* just wrote how that is possible only in theory. I know that. I am interested in whether such a (theoretical) scenario was discussed in the Bitcoin community and what we would do then. One of the solution (mentioned by *noone392*) is to ignore fork (ignore last blocks hash). However, in my opinion, that would not solve anything, because a new last block can be made on top of n-1 th block.  
> **username_0**: @username_1 Yes, I think so too. However, I was interested in what the more experienced "Bitcoin people" think about this topic.  
> **username_3**: While not the same question, I think my answer in username_1's link covers it. It's certainly the case that a very deep reorg is very damaging, but if it were to happen, then the assumptions that make PoW secure are just broken and there is little to be done.  
> **username_0**: @username_3 A reorganization of how many blocks deep could be considered as PoW secure is broken? I'm not asking for an exact number, but an approximate one, from experience. Would 20 block reorg be a serious hit to Bitcoins secure?  

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