I was wondering if I can add dummy data into a coinbase transaction’s inputs. Is it possible to do this? Can you insert invalid input scripts into a coinbase transaction? Can you add multiple inputs scripts into a coinbase, do they all have to be legit scripts, if they do open inputs does the coinbase transaction send more than the regular block reward?
Coinbase transactions must:
- Have exactly 1 input.
- That input must have prevout hash 0000...0000, and index 0xFFFFFFFF (an output which isn't actually spent).
- The input's scriptSig must be between 2 and 100 bytes long.
- Post BIP34 (2012), the scriptSig must start with a push of the block height in little endian encoding.
- Be the first transaction in a block.
If it doesn't satisfy all these rules, the transaction, and the block it is in, are invalid.