I am studing blockhain and i know that a block hash is linked to the next block in previous hash and it cant be changed for valid reason.

Reason is : because if someone have changed hash then then he/she would have to change in hundreds or millions of nodes/system also otherwise it wont be valid.

My question is : If nonce will be changed by some miner then the hash will also get changed and it should be changing the next block's previous hash. correct me if i am wrong. I mean if a miner can change the hash of a block then how he can replicate that hash in all the nodes or system for that block? this is confusing.

1 Answer 1


Miners don't change the hash of a published block, they change the nonce of a block template until the resulting hash is less than the target and only then publish the block.

So until then, there are no other copies that need changing and there are no other blocks that refer to the older failed versions of the published block.

  • you mean they actually add new block and nothing is getting changed in previous block or already published block?
    – Aman
    May 16, 2021 at 10:07
  • @Aman: That is correct. May 16, 2021 at 10:11
  • Thanks for this. nothing is more usefull on the internet for this confusion hence asked the question, as you can see other asnwer on this thread is also not clear. Thank you.
    – Aman
    May 16, 2021 at 10:13

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