<p>I couldn't find a satisfying answer to this 51% attack issue, so for a new blockchain with only 300 mined blocks, from my understanding the attacker has to rebuild all the blocks from scratch, is that true, if yes then what if the blockchain has 100k or 300k blocks? is there a way to prevent or penalize a miner if he mines too fast? does having honest miners would solve the issue? what about multiple Full nodesI need practical solutions</p>

<bitcoin-core>
How to secure a blockchain based on PoW against 51% attack?
zack
# How to secure a blockchain based on PoW against 51% attack?

(Asked by: username_0 on 2021-01-17)

I couldn't find a satisfying answer to this 51% attack issue, so for a new blockchain with only 300 mined blocks, from my understanding the attacker has to rebuild all the blocks from scratch, is that true, if yes then what if the blockchain has 100k or 300k blocks? is there a way to prevent or penalize a miner if he mines too fast? does having honest miners would solve the issue? what about multiple Full nodesI need practical solutions

**Tags:** bitcoin-core


---

## 0 answers

