Therefore, large transactions require more service fee to compensate miners to include the transaction in the block. Transaction signature is over the whole transaction (except the signature itself) => miners cannot modify any portion of the transaction. Pay to Public Key hash (P2PKH) Pay to script hash (P2SH) Funding transaction scriptPk: HASH160 H() EQUAL # Only hash of the script is exposed at the funding time Spending transaction scriptSig: <sig1> <sig2> ....<sigN> <redeemScript> Miner verifies that ScriptSig | ScriptPk -> true => script is correct ScriptSig -> true => script is satisfied This is different from what miner does for P2SH