In mining process, miners validate the block based on proof of work or using some other consensus mechanism. Miners also validate the block. So in this validation process, miners validate only hash value of current block (or) they validate the entire transactions and then they validate the hash value of current block. Please clarify this.

  • But how they check each transaction from block header. Commented Aug 24, 2019 at 16:17

1 Answer 1


Full nodes validate everything. A miner must be running a full node. Not all full nodes are miners, but all miners are full nodes.

A full node validates everything in a block; it validates the transactions, it checks the block header is correct, and checks the Proof of Work is correct. So in the validation process, full nodes (and thus miners) will verify that the PoW is valid (hash of the block header is less than the target), that the block header is correct (contains the correct target, merkle root, etc.). Then they will check that each individual transaction spends UTXOs that exist, check that the scripts validate to true, and check that the output amounts are valid (less than or equal to the input amounts). They will also check that the coinbase transaction pays out the computed maximum payout for the block (subsidy + transaction fees).

  • But how they check each transaction from block header Commented Aug 24, 2019 at 16:18
  • Blocks are more than just the header, they contain transactions. The transactions are sent along with the block header to form an entire block.
    – Ava Chow
    Commented Aug 24, 2019 at 16:31
  • So if i am saying that node A is having some block (B) and other nodes X,Y,Z are wants to validate the block B than node A has to send the block B to nodes X,Y,Z. This block B contains the hash of previous block, time stamp, nonce and Merkele root where Merkle root are created from list of transactions. So Node A send the entire things included the list of transactions to other nodes X,Y,Z or node A send only block excluding the list of transactions for the validation process Commented Aug 24, 2019 at 17:21
  • In general node A will send the entire block B with all of its transactions to nodes X, Y, and Z.
    – Ava Chow
    Commented Aug 24, 2019 at 17:27
  • So if node A send the transactions with block header to other nodes X,Y,Z than it always possible that some one on the way, tempered the transactions so how other nodes validate the transaction. Commented Aug 24, 2019 at 18:26

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