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by Majromax
1824 days ago
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> when bitcoin is under attack, operating them could be a civic measure. Unless I'm gravely mistaken about the bitcoin protocol, you wouldn't know that bitcoin is under a 51% attack until it completes. The 51% attack succeeds when the attacker's blockchain becomes longer than the publicly-accepted blockchain. But there's no reason that the attacker needs to show their work publicly; they can start in secret, mine blocks, and reveal the entire chain at once after it is some number of blocks longer than the public chain. |
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there are 2 parts: one is mining the block, the other is propagating the block.
if you do what you describe, computing blocks would not be enough. you would also need to recompute blocks to account for what happened on the block chain since the split. the more time it passes, the more computing power you would need.
when people talk about 51% attack they usually talk about the double spend issue. this requires 1) a large number of nodes (>51% of the network) and 2) a large amount of hashing power. you would spend some bitcoin, let it be captured in the chain and after that you would fabricate a block that spends the coins differently. now you’ve spent it twice. the miners would pick this as the longer chain and keep going. the important thing to remember is that you cannot keep your chain in the shadows and that this type of attack would be a really hard to pull off (have you ever synchronized a lot of machines to do something? it’s incredibly hard)