diff --git a/09_5_Scripting_a_P2WPKH.md b/09_5_Scripting_a_P2WPKH.md index fb3ced1..8d67022 100644 --- a/09_5_Scripting_a_P2WPKH.md +++ b/09_5_Scripting_a_P2WPKH.md @@ -96,7 +96,7 @@ script | sta ``` Bitcoin Scripts are considered successful if there's something in the Stack, and it's non-zero, so SegWit scripts automatically succeed on old nodes as long as the `scriptPubKey` is correctly created with a non-zero pub-key hash. This is called an "anyone-can-spend" transaction, because old nodes verified them as correct without any need for signatures. -> :book: ***What can't old nodes steal SegWit UTXOs?*** SegWit was enabled on the Bitcoin network when 95% of miners signalled that they were ready to start using it. That means that only 5% of nodes at that point might have registered anyone-can-spend SegWit transactions as valid without going through the proper work of checking the `txinwitness`. If they incorrectly incorporated an invalid anyone-can-spend UTXO into a block, the other 95% of nodes would refuse to validate that block, and so it would quickly be orphaned rather than being added to the "main" blockchain. (Certainly, 51% of nodes could choose to stop interpreting SegWit transactions correctly, but 51% of nodes can do anything on a consensus network like a blockchain.) +> :book: ***Why can't old nodes steal SegWit UTXOs?*** SegWit was enabled on the Bitcoin network when 95% of miners signalled that they were ready to start using it. That means that only 5% of nodes at that point might have registered anyone-can-spend SegWit transactions as valid without going through the proper work of checking the `txinwitness`. If they incorrectly incorporated an invalid anyone-can-spend UTXO into a block, the other 95% of nodes would refuse to validate that block, and so it would quickly be orphaned rather than being added to the "main" blockchain. (Certainly, 51% of nodes could choose to stop interpreting SegWit transactions correctly, but 51% of nodes can do anything on a consensus network like a blockchain.) Because old nodes always see SegWit scripts as correct, they will always verify them, even without understanding their content.