I just saw some video explanations and got to know that a miner with 51% of hashing power can build blockchain faster than any other miner which is pretty obvious.
Also, he can reverse his previous transaction by creating a private blockchain and publishing it later. My question is why he cannot do the same while spending someone else's bitcoin, as he can still build on the previous block containing the invalid transaction, As his power is more than any other miner he will manage to build the longer chain even if other miners refuse to build over the invalid block.
Please, someone, take the pain of explaining this to me.
![Huh](https://bitcointalk.org/Smileys/default/huh.gif)
yes that can be done, the video you have seen is silicon valley.
I dea here is to create a new series of block, which your 51 % share/ miners verify and since a block needs more number of agreeing parties to be valid the blocks created by you are now legitimate and now you hold the right to validate or not validate a transaction or block in the blockchain. This will only be valid for new blocks where your share of hashing or miners are greater than 50%.
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https://bitcointalk.org/index.php?topic=3907169.0