I am relatively new to understanding the fundamentals of the Bitcoin network, and I couldn't find the answer to my question.

I understand how mining difficulty/target is decided and calculated in the block header. (hashrate of previous 2015 blocks...) Since the larger the target is, the easier it is to mine the new block, what stops a miner from cheating by giving himself a large target, so that he can mine this new block very fast? Does every node check the target value when they are validating a new block? Thank you

1 Answer 1


The difficulty target in the block header has to match the currently required difficulty. This value is derived and checked by each node individually from the timestamps and difficulty statements of previous blocks. Then, the block hash of a new block has to adhere to this given difficulty target. If either of the two requirements is not met, other nodes will reject a block as invalid.

So, if a miner ignored either of the rules, they'd of course be able to do that, but then their blocks are simply not accepted by the Bitcoin network.

  • Thank you! I was thinking it should be checked by other nodes also Jul 19, 2020 at 0:45
  • 1
    Every node enforces all rules independently, otherwise they'd have to trust other nodes to provide correct information to them.
    – Murch
    Jul 19, 2020 at 0:49

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