Ethereum: the transaction with a slightly modified script never reverses
As I recently played with Bitcoin transactions, I came across a type of behavior towards the output script in Ethereum transactions. The traditional way of presenting transactions on the Ethereum network uses the following format:
Op_DUP OP_HASH160 (hash) OP_EQUALVERIFY OP_CHECKSIG
This structure allows a hash -based verification, which is essential to ensure the integrity and authenticity of digital signatures.
However, there is an interesting turn of this configuration. When you want to include additional data or slightly change the transaction, you can do so by changing the script in the op_du 'instruction. But what happens when you add a new instruction that interacts with this modified transaction?
The answer is on the Ethereum virtual machine (EVM) and its interaction with scripts. In addition, it has something to do with the concept of "relay fees" and how they affect transactions.
When a transaction is completed in the Ethereum network, the EVM first validates the input data hash. If the hash corresponds to the expected value, the transaction will continue. However, if the hash does not correspond, the transaction will fail.
Now, this is where things are getting interesting. When you add an additional instruction to your transaction that interacts with the modified script (for example, calling a function or updating the variable), EVM checks all relay rates related to this interaction. Relay rates are used to compensate for gas costs to perform sophisticated transactions.
Unfortunately, in most cases, the addition of an additional instruction that changes the original structure of the transaction will cause the "OP_DU" instruction to be performed repeatedly and each time it verifies the different hash value. This means that all subsequent inspections using the modified transaction will fail, as the hash values are no longer valid.
As a result, transactions with slightly modified scripts (ie those that include new instructions or existing changes) can never be transmitted to the Ethereum network. This does not mean that you cannot use these modifications in your applications; They may not work as expected due to the way EVM interacts with scripts and relay rates.
In summary, when playing with Bitcoin transactions, remember that change of scripts using theOP_DUP` instruction can lead to unexpected behavior in the Ethereum network. It is important to understand the basic EVM mechanics and their interactions with scripts before trying to use these modifications in their applications.